Recording medium of stream data, and recording method and playback method of the same

ABSTRACT

Upon playback of stream data which is recorded while being appended with time stamp information in units of packets, time management is made using the time stamp information. A video playback time viewed from the user, which may be indicated by I-, B-, and P-picture display times, is different from the time of the time stamp information. For this reason, when time management for the stream data recorded on an information storage medium is made using only the time stamp information, display time control (video playback time control) for the user cannot be accurately done. In this invention, a time relationship table indicating the relationship between the time stamp information recorded in stream data at each I-picture start time position and display time information (PTS or field information) for the user is provided to a portion of management information.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This is a continuation of Application No. PCT/JP00/00944, filedFeb. 18, 2000.

[0002] This application is based upon and claims the benefit of priorityfrom the prior Japanese Patent Application No. 11-039461, filed Feb. 18,1999, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0003] The present invention relates to an information storage mediumwhich records video data sent in, e.g., digital broadcast, or streamdata sent with a packet structure. Further, the present inventionrelates to a data structure of management information that pertains tostream data recorded on the medium. Still further, the present inventionrelates to a recording method and playback method of the managementinformation.

[0004] In recent years, TV broadcast has come into the era of digitalbroadcast. Accordingly, an apparatus for saving digital data of digitalTV broadcast as it is irrespective of their contents, i.e., a so-calledstreamer, has been demanded.

[0005] The current digital TV broadcast uses an MPEG transport stream.In the future, an MPEG transport stream will be used as a standard onein the field of digital broadcast using moving picture.

[0006] In such digital broadcast, the contents (mainly, videoinformation) to be broadcasted are time-divided into groups of data eachhaving a predetermined size (e.g., 188 bytes) called transport packets,and broadcast data is sent in units of transport packets.

[0007] As a streamer for recording digital broadcast data, a homedigital VCR such as D-VHS (digital VHS) or the like is currentlycommercially available. A streamer using D-VHS directly records abroadcasted bitstream on a tape. For this reason, a plurality ofprograms are multiplexed and recorded on a video tape.

[0008] Upon playback, all data are output from the VCR to a set-top box(digital TV reception apparatus; to be abbreviated as an STBhereinafter) either when they are played back from the beginning or themiddle of the tape. In this STB, a desired program is selected from theoutput data by user operation or the like. The selected programinformation is transferred from the STB to a digital TV receiver, and isplayed back (playback of video plus audio, etc.).

[0009] Since this D-VHS streamer uses a tape as a recording medium, itcannot attain quick random access, and it is difficult to quickly jumpto a desired position of a required program so as to play it back.

[0010] As a promising candidate that can combat such shortcoming(difficulty of random access) of the tape, a streamer that uses alarge-size disc medium such as a DVD-RAM or the like has been proposed.In this case, management data must be inevitably recorded together withbroadcast data in consideration of random access, special playback, andthe like.

[0011] Note that a digital interface that complies with IEEE1394 or thelike can be used in data transfer between the STB as a digital TVreceiver and the stream that uses large-capacity disc media such as aDVD-RAM and the like, or between the streamer that uses large-capacitydisc media and another streamer using a D-VHS or the like.

[0012] In this digital interface, video data/stream data are transferredin units of transport packets received in digital broadcast.

[0013] For example, in a digital interface using IEEE1394, time stampdata indicating the reception time is appended to each transport packetto guarantee real-time transfer of digital broadcast reception data,thus transferring the data.

[0014] Also, in order to guarantee real-time, seamless playback of thedigital broadcast reception data recorded on an information storagemedium such as a DVD-RAM or the like, the time stamp data issimultaneously recorded together with each transport packet data.

[0015] In the aforementioned case, as stream data to be recorded on aninformation storage medium that uses large-capacity disc media such as aDVD-RAM and the like, each transport packet is recorded while beingappended with time stamp data. For this reason, time management is madeusing this time stamp data.

[0016] In digital TV, video data is broadcasted while its information iscompressed using a digital compression scheme called MPEG2. In MPEG2,P-picture information has only differential information from I-picture,and B-picture information has only differential information from I- andP-pictures. Therefore, B- or P-picture cannot be solely played back, andplayback from I-picture is required to playback these pictures.

[0017] Note that the video playback time viewed from the user, which isindicated by display times of I-, B-, and P-pictures, is different fromthe time stamp information. For this reason, when time management forstream data recorded on the information storage medium is made usingonly the time stamp data, control of the display time (video playbacktime) for the user cannot be accurately made.

[0018] The present invention has been made to solve the aforementionedproblem, and has as its object to provide a data structure of managementinformation, and a recording method and playback method of the same,which make time management of stream data using time stamp data recordedin the stream data, and can make accurate time display control for theuser.

BRIEF SUMMARY OF THE INVENTION

[0019] In order to achieve the above object, according to the presentinvention, information (time relationship table; or playback time stamplist PTSL) that indicates the relationship between time stamp data(application time stamp ATS) recorded in stream data, and display timeinformation (PTS or field information) for the user is provided to aportion of management information (stream file information table SFIT).

[0020] On the other hand, the relationship among the display timeinformation (PTS or field information) for the user, the start timeposition of each I-picture (or access unit start map AUSM indicatingstream object unit SOBU to which target access unit AU belongs), andtime stamp data (ATS) can be indicated by the time relationship table(or PTSL).

[0021] An information medium according to the present invention has adata area (STREAM.VRO/SR_TRANS.SRO) where stream data (SOB or SOBU) canbe recorded in a predetermined data recording unit (transportpacket/application packet), and a management area(STREAM.IFO/SR_MANGR.IFO) where management information (STRI) thatpertains to the stream data can be recorded. The management information(STRI) can record: first management information (ATS corresponding toI-picture transfer start time; or AUSM) used to access the stream data(access I-picture information or AU); and third management information(time relationship table; or PTSL) which is different from the firstmanagement information (AUSM), and indicates a relationship between thefirst management information and second management information (PTS; orcell start APAT=SC_S_APAT) used to access the stream data.

[0022] A recording method according to the present invention uses aninformation medium (201) which has a data area (STREAM.VRO) where streamdata (SOB or SOBU) can be recorded in a predetermined data recordingunit (packet), and a management area (STREAM.IFO) where managementinformation (STRI) that pertains to the stream data can be recorded. Themanagement information (STRI) can record: first management information(ATS corresponding to I-picture transfer start time; or AUSM) used toaccess the stream data (access I-picture information or AU); and thirdmanagement information (time relationship table; or PTSL) which isdifferent from the first management information (AUSM), and indicates arelationship between the first management information and secondmanagement information (PTS; or SC_S_APAT) used to access the streamdata (AU).

[0023] Upon recording on such information medium, the first managementinformation (ATS/AUSM) is extracted from stream data to be recorded(step S03); the second management information (PTS) is extracted fromthe stream data to be recorded (step S04); the stream data (packet data)is recorded on the information medium (201) (step S07); and the thirdmanagement information (time relationship table/PTSL) is recorded on themanagement area (STREAM.IFO/SR_MANGR.IFO) (step S11).

[0024] Alternatively, upon recording on such information medium, asynchronization process of a predetermined reference clock (SCR) isexecuted between a stream data supply device (STB unit) and a streamdata recording device (optical disc device or optical disc drive) (stepS54); the third management information (time relationship table; orPTSL) is corrected or modified on the basis of a result of thesynchronization process of the reference clock (SCR) (step S56); and thecorrected or modified third management information (time relationshiptable; or PTSL) is recorded in the management area(STREAM.IFO/SR_MANGR.IFO) on the information medium (201) (step S57).

[0025] A playback method according to the present invention uses aninformation medium (201) which has a data area (STREAM.VRO/SR_TRANS.SRO)where stream data can be recorded in a second data unit (SOBU) includinga first data recording unit (application packet AP), and a managementarea (STREAM.IFO/SR_MANGR.IFO) where management information (STRI) thatpertains to the stream data can be recorded. The management information(STRI) can record: first management information (ATS corresponding toI-picture transfer start time; or AUSM) used to access the stream data(access I-picture information or AU); and third management information(time relationship table; or PTSL) which is different from the firstmanagement information (AUSM), and indicates a relationship between thefirst management information and second management information (PTS; orSC_S_APAT) used to access the stream data (AU).

[0026] Upon playing back the stream data from such information medium(201), when the stream data has a plurality of continuous second dataunits (for example, SOBU#1 and SOBU#2), a position difference (PTSoffset or AP which is not played back in FIG. 29(g)) from a neighboringboundary position of the plurality of continuous second data units(SOBU#1 and SOBU#2) to a position (SC_S_APAT) of the first datarecording unit (AP) indicated by the second management information (PTS;or SC_S_APAT) is checked (step S24); read of the stream data recorded onthe information medium (201) starts from the neighboring boundaryposition (step S30) but read data until the position (SC_S_APAT) of thefirst data recording unit (AP) indicated by the position difference arediscarded or ignored (step S31); and playback (display of playbackinformation) of the stream data recorded on the information medium (201)starts from the position (SC_S_APAT) of the first data recording unit(AP) indicated by the position difference (step S32).

[0027] Alternatively, upon playback from such information medium, astart address of the second data unit (SOBU) including the firstmanagement information (ATS corresponding to I-picture transfer starttime; or AUSM) is checked (step S45); playback information other than anaccess position (access position of I-picture information or AU) of thestream data indicated as the first management information (AUSM) isdiscarded or ignored using the checked start address of the second dataunit (step S47); and only playback information at the access position(I-picture information; or AU) of the stream data is sequentially playedback or displayed (step S49).

[0028] Additional objects and advantages of the invention will be setforth in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention may be realized and obtained bymeans of the instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0029] The accompanying drawings, which are incorporated in andconstitute a part of the specification, illustrate presently preferredembodiments of the invention, and together with the general descriptiongiven above and the detailed description of the preferred embodimentsgiven below, serve to explain the principles of the invention.

[0030]FIG. 1 is a view for explaining the data structure of stream dataaccording to an embodiment of the present invention;

[0031]FIG. 2 is a view for explaining the directory structure of datafiles according to an embodiment of the present invention;

[0032]FIG. 3 is a view for explaining the recorded data structure(especially, the structure of management information) on an informationmedium (recordable/reproducible DVD disc) according to an embodiment ofthe present invention;

[0033]FIG. 4 is a view for explaining the relationship among streamobjects (SOB), cells, program chains (PGC), and the like in the presentinvention;

[0034]FIG. 5 is a view for explaining the contents of a stream blocksize, stream block time difference, and the like in time mapinformation;

[0035]FIG. 6 is a view for explaining the cell range designation methodin an original cell and user-defined cell;

[0036]FIG. 7 is a view for explaining the recorded data structure(especially, the structure of playback end position information/resumeinformation, VMGI management information/recording time information, andthe like) on an information medium (recordable/reproducible DVD disc)according to another embodiment of the present invention;

[0037]FIG. 8 is a view for explaining the internal structure of a PESheader shown in FIG. 1 and the like;

[0038]FIG. 9 is a view for explaining the internal structure of a streamblock header shown in FIG. 1;

[0039]FIG. 10 is a view for explaining the internal structure of asector data header shown in FIG. 1;

[0040]FIG. 11 is a view for explaining another example of time mapinformation in an embodiment of the present invention;

[0041]FIG. 12 is a view for explaining an example of the internalstructure (a stream pack containing application packets and a streampack containing stuffing packets) of a sector that forms a stream block(SOBU);

[0042]FIG. 13 is a view for explaining the internal data structure ofmanagement information (STREAM.IFO or SR_MANGR.IFO in FIG. 2) of thestreamer;

[0043]FIG. 14 is a view for explaining the internal data structure ofPGC information (ORG_PGCI/UD_PGCIT in FIG. 3 or PGCI#i in FIG. 13);

[0044]FIG. 15 is a view for explaining the internal data structure of astream file information table (SFIT);

[0045]FIG. 16 is a view exemplifying the correspondence between anaccess unit start map (AUSM) and stream object unit (SOBU);

[0046]FIG. 17 is a view exemplifying the correspondence between anaccess unit start map (AUSM) and access unit end map (AUEM), and streamobject unit (SOBU);

[0047]FIG. 18 is a view for explaining the relationship between cellsdesignated by an original or user-defined PGC and SOBUs corresponding tothese cells via time map information;

[0048]FIG. 19 is a block diagram for explaining the arrangement of astream data recording/playback apparatus (optical disc device/streamer,STB unit) according to an embodiment of the present invention;

[0049]FIG. 20 is a view for explaining a time relationship tableindicating the relationship between the display time and data transfertime in an embodiment of the present invention;

[0050]FIG. 21 is a view for explaining the relationship between thedisplay time and data transfer time in an embodiment of the presentinvention;

[0051]FIG. 22 is a view for explaining the relationship between thevideo information compression method in MPEG and transport packets, andthe relationship between transport packets in MPEG and applicationpackets in the streamer;

[0052]FIG. 23 is a view for explaining the correspondence among thedigital broadcast contents, the video data transfer format in IEEE1394,and stream packs in the streamer;

[0053]FIG. 24 is a flow chart for explaining the recording sequence ofstream data according to an embodiment of the present invention;

[0054]FIG. 25 is a flow chart for explaining the recording sequence ofencrypted stream data according to an embodiment of the presentinvention;

[0055]FIG. 26 is a flow chart for explaining the playback sequence ofstream data according to an embodiment of the present invention;

[0056]FIG. 27 is a flow chart for explaining the special playbacksequence of stream data according to an embodiment of the presentinvention;

[0057]FIG. 28 is a view for explaining a time relationship tableindicating the relationship between the display time and data transfertime in another embodiment of the present invention; and

[0058]FIG. 29 is a view for explaining the way packets (AP) in streamdata (SOBU) are played back in an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0059] A stream data storage medium according to an embodiment of thepresent invention, the data structure of management data that pertainsto stream data recorded on the medium, a recording method and playbackmethod of the management information, and so on will be describedhereinafter with reference to the accompanying drawings.

[0060]FIG. 1 is a view for explaining the data structure of stream dataaccording to an embodiment of the present invention. The data structureof stream data recorded on an information storage medium will bedescribed using FIG. 1.

[0061] Stream data (STREAM.VRO) 106 (FIG. 1(a)) recorded on aninformation storage medium (201 in FIG. 3 and the like) such as aDVD-RAM disc or the like are combined as stream objects (to beabbreviated as SOBs hereinafter as needed) in units of contents of videoinformation in stream data. Each SOB is formed of stream data obtainedby single real-time, continuous recording.

[0062] As shown in FIG. 1(b), stream data recorded on the informationstorage medium are recorded together as stream objects (SOB) #A·298 and#B·299 in units of contents of video information in the stream data.

[0063] FIGS. 1(b) to (k) show details of contents of one SOB#A·298 of aplurality of stream objects (SOB#A, #B, . . . ).

[0064] Upon recording stream data (STREAM.VRO) 106 on a DVD-RAM disc,each data is recorded using 2,048-byte sectors as minimum units.Furthermore, 16 sectors form one ECC block, and in one ECC block, dataare interleaved (the order of data is re-arranged) and a correction codefor error correction is appended.

[0065] In this embodiment, a stream block (or stream object unit SOBU)is formed by one or more (typically, 2) of ECC blocks as a unit, andstream information undergoes recording, partial erase, edit, and thelike in units of stream blocks (or SOBUs).

[0066] In this embodiment, the number of ECC blocks that form a streamblock can be determined in accordance with the transfer rate of streamdata (STREAM.VRO) 106 to be transferred.

[0067] For example, in an example shown in FIGS. 1(c) and (d), streamblock #1 is formed by two ECC blocks #α and #β, and stream block #2 isformed by three ECC blocks #γ, #δ, and #ε. A DVD streamer forms onestream block (or SOBU) using two ECC blocks (32 sectors).

[0068] Each ECC block is made up of 16 sectors, as shown in FIG. 1(e).Therefore, as can be seen from FIGS. 1(c) to (e), stream block (or SOBU)#1 made up of two ECC blocks corresponds to 32 sectors (sectors No. 0 toNo. 31).

[0069] More specifically, if one sector=2 k bytes, a stream block (SOBU)has a fixed size of 64 k bytes (32 sectors) upon practicing the presentinvention.

[0070] Stream data (STREAM.VRO) 106 is recorded on the informationstorage medium as pairs of time stamps and transport time packets, asshown in FIG. 1(g).

[0071] In such case, pack headers 11 and 12 that record system clockinformation (system clock reference SCR) and the like and PES headers 13and 14 are allocated at the head positions of the respective sectors, asshown in FIG. 1(f). Sector data header 17 is recorded immediately afterPES header 14, but stream block header 16 is recorded in only the firstsector of each stream block (or SOBU) in place of the sector dataheader.

[0072] Note that stream block header 16 or sector data header 17 canhave contents corresponding to an application header (to be describedlater) (see FIG. 9 or FIG. 10).

[0073] Sector data header 17 in FIG. 1(f) indicates data layoutinformation in data areas 22 and 23.

[0074] Data areas 21 and 22 (or 23) in FIG. 1(f) are stuffed in turnwith time stamps (corresponding to ATS shown in FIG. 20, FIG. 29, etc.)and transport packets (corresponding to packets shown in FIG. 22 or FIG.23 or application packets AP in FIG. 29), as shown in FIG. 1(g).

[0075] In the example shown in FIG. 1(g), single transport packet d isrecorded across a plurality of sectors (No. 0 and No. 1). Such transportpacket d corresponds to a partial packet in FIG. 22 or FIG. 23.

[0076] Digital broadcast adopts a multi-program compatiblemultiplexing/demultiplexing scheme called a transport stream, and onetransport packet often normally has a size of 188 bytes (or 183 bytes).

[0077] On the other hand, one sector size is 2,048 bytes, as describedabove, and each of data areas 21, 22, and 23 (FIG. 1(f)) can recordapproximately 10 transport packets for digital broadcast even aftervarious header sizes are subtracted.

[0078] Each transport packet is made up of a corresponding one oftransport packet headers 61 to 64 (corresponding to 511 in FIG. 23(b) tobe described later), and a corresponding one of payloads 71 to 75(corresponding to 512 in FIG. 23(b) to be described later) that recorddata, as shown in FIG. 1(h).

[0079] Each of payloads 71 to 75 records MPEG-encoded I-pictureinformation 31, B-picture information 33, B-picture information 34, andP-picture information 32, as shown in FIG. 1(i).

[0080] In the first transport packet that records I-picture information31, random access indicator 503 (see FIG. 23(a)) is set with flag=“1”.On the other hand, in the first transport packets of B-pictureinformation and P-picture information (32 to 34), payload unit startindicator 501 (see FIG. 23(a)) is set with flag= “1”.

[0081] In each picture information (31 to 34) divisionally recorded inpayloads 71 to 75, picture header information 41, picture compressedinformation 42 (I-picture compressed information 42 for I-pictureinformation 31) as actual picture information are recorded, as shown inFIG. 1(j).

[0082] Each picture header information 41 records header identificationinformation 51, picture identification information 52 that can identifyI-, B-, or P-picture, PTS (presentation time stamp) information 53indicating the display timing of a decoder output, and DTS (decode timestamp) information 54 indicating the timing at which a decoder begins todecode, as shown in FIG. 1(k). Such picture header information 41 isincluded in advance in broadcast reception information.

[0083] In stream data recorded on the information storage medium, aspecific picture position can be identified using picture identificationinformation 52 shown in FIG. 1(k).

[0084] Alternatively, since PTS information 53 is recorded in pictureheader information 41, as shown in FIGS. 1(j) and (k), the decoder canstart display using this value.

[0085]FIG. 2 is a view for explaining the directory structure of datafiles according to an embodiment of the present invention. The contents(file structure) of information recorded on the information storagemedium according to an embodiment of the present invention will beexplained below.

[0086] Each information recorded on an information storage medium suchas a DVD-RAM disc or the like has a hierarchical file structure. Videoinformation and stream data information to be explained in thisembodiment are stored in subdirectory 101 named DVD_RTR directory (orDVD_RTAV) 102.

[0087] DVD_RTR (DVD_RTAV) directory 102 stores data file 103 having thefollowing contents.

[0088] More specifically, as a group of management information(navigation data), RTR.IFO (VR_MANGR.IFO) 104, STREAM.IFO(SR_MANGR.IFO/SR_MANGR.BUP) 105, and SR_PRIVT.DAT/SR_PRIVT.BUP 105 a arestored.

[0089] As a data main body (contents information), STREAM.VRO(SR_TRANS.SRO) 106, RTR_MOV.VRO (VR_MOVIE.VRO) 107, RTR_STO.VRO (orVR_STILL.VRO) 108, and RTR_STA.VRO (or VR_AUDIO.VRO) 109 are stored.

[0090] Root directory 100 as an upper layer of subdirectory 101including data file 103 can be provided with subdirectory 110 forstoring other kinds of information.

[0091] This subdirectory includes, as its contents, video title setVIDEO_TS 111 that stores video programs, audio title set AUDIO_TS 112that stores audio programs, subdirectory 113 for saving computer data,etc.

[0092] Data which is transmitted on a wired or wireless datacommunication path in the form of a packet structure and is recorded onan information storage medium while holding the packet structure iscalled “stream data”.

[0093] The stream data themselves are recorded together with file nameSTREAM.VRO (or SR_TRANS.SRO) 106. A file that records managementinformation of the stream data is STREAM.IFO (or SR_MANGR.IFO and itsbackup file SR_MANGR.BUP) 105.

[0094] A file that records analog video information which is used in aVCR (VTR) or conventional TV and is digitally compressed based on MPEG2is RTR_MOV.VRO (or VR_MOVIE.VRO) 107, a file that collects still pictureinformation including postrecorded audio, background audio, or the likeis RTR_STO.VRO (or VR_STILL.VRO) 108, and its postrecorded audioinformation file is RTR_STA.VRO (or VR_AUDIO.VRO) 109.

[0095]FIG. 3 is a view for explaining the recorded data structure(especially, the structure of management information) on an informationmedium (recordable/reproducible DVD disc) according to an embodiment ofthe present invention.

[0096] In an area sandwiched between the ends of inner circumferentialdirection 202 and outer circumferential direction 203 of informationstorage medium 201 shown in FIG. 3(a), lead-in area 204, volume & filestructure information 206 that records file system information, dataarea 207, and lead-out area 205 are present, as shown in FIG. 3(b).Lead-in area 204 is made up of an emboss zone and rewritable data zone,and lead-out area 205 is made up of a rewritable data zone. Data area207 is also made up of a rewritable data zone.

[0097] Data area 207 can record computer data and audio & video datatogether, as shown in FIG. 3(c). In this example, audio & video dataarea 210 is sandwiched between computer data areas 208 and 209.

[0098] Audio & video data area 210 can record real-time video recordingarea 221 and stream recording area 222 together, as shown in FIG. 3(d).(Either of real-time video recording area 221 or stream recording area222 can be used.)

[0099] As shown in FIG. 3(e), real-time video recording area 221 recordsRTR navigation data RTR.IFO (VR_MANGR.IFO) 104, movie real-time videoobject RTR_MOV.VRO (VR_MOVIE.VRO) 107, still picture real-time videoobject RTR_STO.VRO (VR_STILL.VRO) 108, and audio object RTR_STA.VRO(VR_AUDIO.VRO) 109 such as postrecorded audio or the like, which areshown in FIG. 2.

[0100] Also, as shown in FIG. 3(e), stream recording area 222 recordsstreamer navigation data STREAM.IFO (SR_MANGR.IFO/SR_MANGR.BUP) 105 andtransport bitstream data STREAM.VRO (SR_TRANS.SRO) 106, which are shownin FIG. 2.

[0101] Note that stream recording area 222 can also record navigationdata SR_PRIVT.DAT/SR_PRIVT.BUP 105 a unique to an application shown inFIG. 2, although not shown in FIGS. 3(d) and (e).

[0102] This SR_PRIVT.DAT 105 a is navigation data unique to anindividual application connected (supplied) to the streamer, and neednot be recognized by the streamer.

[0103] STREAM.IFO (or SR_MANGR.IFO) 105 as management information thatpertains to stream data has a data structure shown in FIGS. 3(f) to (i).

[0104] More specifically, as shown in FIG. 3(f), STREAM.IFO (orSR_MANGR.IFO) 105 is comprised of video manager (VMGI or STR_VMGI) 231,stream file information table (SFIT) 232, original PGC information(ORG_PGCI) 233, user-defined PGC information table (UD_PGCIT) 234, textdata manager (TXTDT_MG) 235, and manufacturer information table (MNFIT)or application private data manager (APDT_MG) 236 that managesnavigation data SR_PRIVT.DAT 105 a unique to an application.

[0105] Stream file information table (SFIT) 232 shown in FIG. 3(f) cancontain stream file information table information (SFITI) 241, one ormore pieces of stream object information (SOBI) #A·242, #B·243, . . . ,original PGC information general information 271, and one or more piecesof original cell information #1·272, #2·273, . . . , as shown in FIG.3(g).

[0106] Each stream object information (e.g., SOBI#A·242) shown in FIG.3(g) can contain stream object general information (SOBI_GI) 251, timemap information 252, and the like, as shown in FIG. 3(h).

[0107] Each original cell information (e.g., #1·272; corresponding toSCI shown in FIG. 14 to be described later) shown in FIG. 3(g) cancontain cell type 281 (corresponding to C_TY shown in FIG. 14 to bedescribed later), cell ID 282, corresponding cell start time(corresponding to SC_S_APAT shown in FIG. 6(b), FIG. 14, etc. to bedescribed later) 283, corresponding cell end time (corresponding toSC_E_APAT shown in FIG. 6(b), FIG. 14, etc. to be described later) 284,PTS offset 9, and time relationship table 2, as shown in FIG. 3(h).

[0108] Note that PTS offset 9 indicates the difference between the PTS(presentation time stamp value) of a display start picture of anoriginal cell (details of the original cell will be explained later) andthat of I-picture located immediately before the display start picture(details will be explained later with reference to FIG. 20).

[0109] Time map information 252 in FIG. 3(h), which is contained inSOBI#A in FIG. 3(g) can include stream block number 261, first streamblock size 262, first stream block time difference 263, second streamblock size 264, second stream block time difference 265, . . . , asshown in FIG. 3(i). The contents of each stream block time differencethat forms time map information 252 will be explained later withreference to FIG. 5.

[0110]FIG. 4 is a view for explaining the relationship among streamobjects (SOB), cells, program chains (PGC), and the like in anembodiment of the present invention. The relationship between SOB andPGC in the present invention will be explained below using an exampleshown in FIG. 4.

[0111] Stream data recorded in stream data (STREAM.VRO or SR_TRANS.SRO)106 form stream blocks as sets of one or more ECC blocks, and recording,a partial erase process, and the like are done in units of streamblocks. The stream data form groups called stream objects in units ofcontents of information to be recorded (e.g., in units of programs indigital broadcast).

[0112] Management information (original PGC information 233,user-defined PGC information table 234, or the like) for each streamobject (SOB#A, SOB#B) recorded in STREAM.VRO (SR_TRANS.SRO) 106 isrecorded in navigation data STREAM.IFO (SR_MANGR.IFO) 105 (see lowermostportion in FIG. 4 and FIGS. 3(e) and (f)).

[0113] Two pieces of management information (STREAM.IFO 105) for streamobjects #A·298 and #B·299 in FIG. 4 are recorded as two pieces of streamobject information (SOBI) #A·242 and #B·243 in stream file informationtable (SFIT) 232, as shown in FIGS. 3(f) and (g).

[0114] Each of stream object information (SOBI) #A·242 and #B243contains time map information 252 that mainly describes the data size,time information, and the like in units of stream blocks.

[0115] Upon playing back stream data, information (corresponding toPGCI#i in FIG. 14 to be described later) of a program chain (PGC) madeup of one or more successive cells is used. Stream data can be playedback in accordance with the order in which the cells that form this PGCare set.

[0116] There are two types of PGCs, i.e., original PGC 290 (ORG_PGCI·233in FIG. 3(f)) which can continuously play back all stream data recordedin STREAM.VRO (SR_TRANS.SRO) 106, and user-defined PGCs #a·293 and#b·296 (corresponding to the contents of UD_PGCIT·234 in FIG. 3(f)) thatcan set arbitrary locations and order of user choice.

[0117] Original cells #1·291 and #2·292 that form original PGC 290basically have one-to-one correspondence with stream objects #A·298 and#B·299.

[0118] By contrast, user-defined cells #11·294, #12·295, and #31·297that form the user-defined PGC can set arbitrary locations within therange of one stream object #A·298 or #B·299.

[0119] Note that the sector size of each stream block can be variouslyset. As a preferred embodiment, a stream object unit (SOBU) made up oftwo ECC blocks (32 sectors) and having a constant size (64 k bytes) canbe used as a stream block like stream block #1 in FIG. 4.

[0120] When the stream block is fixed to be an SOBU having a constantsize (e.g., 2 ECC blocks=32 sectors= 64 k bytes), the following meritsare obtained.

[0121] (01) Even when stream data is erased or rewritten in units ofSOBUS, an ECC block of that SOBU does not influence ECC blocks of SOBUsother than the SOBU to be erased or rewritten. For this reason, ECCdeinterleave/interleave upon erase or rewrite (for SOBUs other than theSOBU to be erased or rewritten) need not be done; and

[0122] (02) An access position to recorded information in an arbitrarySOBU can be specified by the number of sectors (or a parametercorresponding to the number of sectors; e.g., information of streampacks or application packets therein shown in FIG. 10 to be describedlater). For example, when the middle position of given SOBU#k is to beaccessed, the 16th sector position (or application packet positioncorresponding to the 16th sector position) from the boundary betweenSOBU#k-1 and SOBU#k can be designated.

[0123]FIG. 5 is a view for explaining the contents of the stream blocksize and stream block time difference in the time map information. Thecontents of individual data in time map information 252 will beexplained below using FIG. 5.

[0124] As exemplified in FIG. 5(f), FIG. 5(g), and FIG. 5(h), streamobject (SOB) #A·298 is made up of stream blocks #1 and #2.

[0125] In the example shown in FIGS. 5(f) and (h), the data size ofstream block #1 that forms SOB#A·298 is defined by two ECC blocks (#αand #β), i.e., 32 sectors (FIG. 5(e) and (i)). That is, first streamblock size 262 (FIG. 5(j)) in time map information 252 (FIG. 5(a) andFIG. 5(k)) is 32 sectors (64 k bytes).

[0126] Stream block #1 (FIG. 5(f)) located at the head position ofSOB#A·298 (FIG. 5(g)) has sector No. 0 (FIG. 5(e)) at its head position,and time stamp a is recorded at the head position of data area 21 (FIG.5(d)) included in sector No. 0.

[0127] Subsequent stream block #2 (FIG. 5(f)) of SOB#A·298 (FIG. 5(g))has sector No. 32 (FIG. 5(e)), and time stamp p (FIG. 5(c)) is recordedat the head position of data area 311 (FIG. 5(d)) included in sector No.32.

[0128] As shown in FIG. 5(c), the time stamp value of the first streamdata in stream block #1 is time stamp a, and that of the first streamdata of next stream block #2 is time stamp p.

[0129] The value of first stream block time difference 263 in FIG. 5(b)(corresponding to stream block time difference 263 in FIG. 3(i)) isgiven by the difference ([time stamp p]−[time stamp a]) between timestamps a and p.

[0130] Note that time map information 252 in FIG. 5(a) can be handled asinformation including access data unit AUD in stream object informationSOBI to be described later with reference to FIG. 15. Information(access unit start map AUSM and the like) included in this AUD canspecify an SOBU that includes information to be accessed.

[0131]FIG. 6 is a view for explaining the cell range designation methodin an original cell and user-defined cell. The cell range can bedesignated by designating the start and end times.

[0132] More specifically, the values of first time stamp a and last timestamp z (FIG. 6(c)) in corresponding stream object #A·298 (FIG. 6(f))are used as the values of corresponding cell start and end times 283 and284 (FIG. 6(b)) in an original immediately after recording of streamdata.

[0133] By contrast, the time range in user-defined cell #12·295 (FIG.6(k)) can designate arbitrary times. For example, as shown in FIGS. 6(i)and (j), the values of time stamps d and n corresponding to designatedtransport packets d and n can be set as the values of corresponding cellstart and end times 331 and 332.

[0134]FIG. 6(f) exemplifies a case wherein stream object (SOB) #A·298 ismade up of two stream blocks #1 and #2.

[0135] In the example shown in FIGS. 6(e) and (g), stream block #1consists of 32 sectors (sectors No. 0 to No. 31), and stream block #2consists of 48 sectors (sectors No. 32 to No. 79).

[0136] First sector No. 0 in stream block #1 is comprised of pack header1, PES header 6, stream block header 11, data area 21, and the like, asshown in FIGS. 6(e) and (d).

[0137] On the other hand, trailing-side sector No. 78 in stream block #2is comprised of pack header 3, PES header 8, sector data header 13, dataarea 24, and the like, as shown in FIGS. 6(e) and (d).

[0138] Furthermore, sector No. 1 in FIG. 6(g) records pack header 2,sector data header 12, data area 22, and the like, as shown in FIG.6(h), and sector No. 33 in FIG. 6(g) records sector data header 321,data area 312, and the like, as shown in FIG. 6(h).

[0139] Data area 21 shown in FIGS. 6(d) and (h) records pairs of timestamps a to d and transport packets a to d, as shown in FIGS. 6(c) and(i).

[0140] Also, data area 24 in FIG. 6(d) records a plurality of pairs oftime stamps and transport packets, end code 32 that follows the lastpair of time stamp z+ transport packet z, and padding area 37.

[0141] Data area 22 shown in FIG. 6(h) includes transport packet d thatincludes the remaining contents of transport packet d in data area 21,as shown in FIG. 6(i). That is, in this example, the contents oftransport packet d are divisionally recorded in data areas 21 and 22.

[0142] The former half (on the data area 21 side) of transport packet din FIG. 6(i) corresponds to a tail-side partial packet in FIG. 23(f) tobe described later, and the latter half (on the data area 22 side) oftransport packet d in FIG. 6(i) corresponds to a head-side partialpacket in FIG. 23(g) to be described later.

[0143] Furthermore, data area 312 in FIG. 6(h) records a pair of timestamp n and transport packet n, and other similar pairs, as shown inFIG. 6(i).

[0144] Note that start time 331 (FIG. 6(j)) of a cell corresponding to aposition where the user or the like designates the playback start timeis designated by time stamp d (FIG. 6(i)) for the total of two transportpackets d divisionally recorded in data areas 21 and 22.

[0145] When a transport packet is changed to read an application packet(AP) and APAT represents the application packet arrival time, cell starttime 331 can be expressed by cell start APAT.

[0146] On the other hand, end time 332 (FIG. 6(j)) of a cellcorresponding to a position where the user or the like designates theplayback end time is designated by time stamp n (FIG. 6(i)) fortransport packet n in data area 312. This cell end time 332 can beexpressed as cell end APAT.

[0147] The aforementioned cell start time (cell start APAT) 331 and cellend time (cell end APAT) 332 are recorded in user-defined cellinformation #12·295, as shown in FIG. 6(k).

[0148] This user-defined cell information #12·295 can be recorded inuser-defined PGC information table 234 shown in FIG. 3(f) or the lowerportion in FIG. 4.

[0149] The cell start start/end time information that pertains to theuser-defined cell information (information of a user-defined PGC) hasbeen explained. On the other hand, cell start/end time information thatpertains to original cell information (information of an original cell)can be exemplified as follows.

[0150] More specifically, head-side time stamp a in FIG. 6(c) canindicate corresponding cell start time 293 in FIG. 6(b), and tail-sidetime stamp z can indicate corresponding cell end time 284.

[0151] Corresponding cell start time 283 in FIG. 6(b) can correspond tocell start APAT (including stream cell start APAT (SC_S_APAT) or erasestart APAT (ERA_S_APAT) to be described later).

[0152] Corresponding cell end time 284 in FIG. 6(b) can correspond tocell end APAT (including stream cell end APAT (SC_E_APAT) or erase endAPAT (ERA_E_APAT) to be described later).

[0153] The aforementioned cell start time (cell start APAT) 283 and cellend time (cell end APAT) 284 are recorded in original cell information#1·272, as shown in FIG. 6(a).

[0154] This original cell information #1·272 can be recorded in originalcell PGC information 233 shown in FIG. 3(f) or the lower portion in FIG.4.

[0155]FIG. 7 is a view for explaining the recorded data structure(especially, the structure of playback end position information/resumeinformation, VMGI management information/recording time information, andthe like) on an information medium (recordable/reproducible DVD disc)according to another embodiment of the present invention.

[0156] Since the data format shown in FIGS. 7(a) to (f) is the same asthat shown in FIGS. 3(a) to (f), a description thereof will be omitted.

[0157] Video manager (STR_VMGI) 231 in FIG. 7(f) contains playback endposition information (resume information) 6110, video manager managementinformation (VMGI_MAT) 6111, and the like, as shown in FIG. 7(g).

[0158] Playback end position information (resume information) 6110includes original PGC number 6210, original cell number 6220, playbackend position time (resume time) information 6230, and the like, as shownin FIG. 7(h).

[0159] Video manager management information (VMGI_MAT) 6111 includestime zone (TM_ZONE) 6240.

[0160] Upon completion of playback of the recorded stream block (ororiginal cell), playback end position information 6110 can be recordedin video manager information 231 in a management information recordingarea (STREAM.IFO) in FIG. 7(e) as resume information.

[0161] Note that time information 6230 included in playback end positioninformation 6110 is recorded using a time stamp (ATS) value. However,the present invention is not limited to such specific value, and a PTSvalue (or a total number of fields from the cell playback startposition) may be recorded as time information 6230.

[0162] Time zone (TM_ZONE) 6240 includes information of a recording time(REC_TM), as shown in FIG. 7(i).

[0163] The information of the recording time (REC_TM) includes a timezone type (TZ_TY) used to identify if REC_TM is based on universal timecoordinate (UTC) or specific local time, and a time zone offset(TZ_OFFSET) that describes the time offset of REC_TM from UTC in unitsof minutes.

[0164] The recording time (REC_TM) may be described in the form of acell start time (SC_S_APAT) shown in FIG. 6(b) and the like or in theform of playback time (presentation time PTM) of that cell.

[0165] There are two types of recording time (REC_TM). The first one isa stream object recording time (SOB_REC_TM), and the second one is aplay list creation time (PL_CREATE_TM).

[0166] Note that the time at which a stream object (SOB) correspondingto an original cell was recorded is indicated by SOB_REC_TM.

[0167] Note that the play list is a list of a portion of a program. Withthis play list, the user can define an arbitrary playback sequence (forthe contents of a program). The time at which such play list was createdis indicated by PL_ CREATE_TM.

[0168]FIG. 8 is a view for explaining the internal structure of a PESheader shown in FIG. 1 and the like.

[0169] PES header 601 in FIG. 8(a) includes packet start code prefix602, stream ID 603, playback time stamp 604, and the like, as shown inFIG. 8(b). This PES header 601 corresponds to the PES header shown inFIG. 1(f), FIG. 5(d), FIG. 6(d), etc.

[0170] A stream PES header in FIG. 8(d) includes a packet start codeprefix, stream ID (private stream 2), PES packet length, substream ID,and the like, as shown in FIG. 8(c). This stream PES header is the sameas that shown in FIG. 22 to be described later, and has contentscorresponding to PES header 601 in FIG. 8(a).

[0171] When the PES header in FIG. 1(f) has the internal structure ofPES header 601 shown in FIG. 8(a), if stream ID 603 (FIG. 8(b)) of thisPES header is “10111110”, a packet having this PES header is defined tobe a padding packet (see FIG. 12(g) to be described later) in MPEG.

[0172] On the other hand, if substream ID 603 (substream ID in FIG.8(c)) is “00000010”, a packet with that PES header includes streamrecording data.

[0173] In stream block #1 in FIG. 1(c), last transport packet g (FIG.1(g)) is present within sectors No. 0 to No. 31 (FIG. 1(e)). However, instream block #2 (FIGS. 1(e) and (g)), since the user or the like endsvideo recording halfway through, the last transport packet (not shown)is allocated in a sector before the last one, and the last sector (notshown) is often a free area where no stream data is recorded. In thiscase, the padding packet (padding packet 40 in FIG. 12(g) to bedescribed later) is recorded in the last sector.

[0174]FIG. 9 is a view for explaining the internal structure of thestream block header shown in FIG. 1.

[0175] As shown in FIG. 9(a), stream block header 11 has contentscorresponding to a substream ID, application header, application headerextension, stuffing byte, and the like.

[0176] The 1-byte application header extension (option) describes 1-bitAU_START, 1-bit AU_END, and 2-bit COPYRIGHT.

[0177] When AU_START is set at “1”, it indicates that a relatedapplication packet (e.g., AP in FIG. 29) includes a random access entrypoint (start of a random access unit) within the stream.

[0178] When AU_END is set at “1”, it indicates that a relatedapplication packet is the last packet of the random access unit.

[0179] COPYRIGHT describes the state of the copyright of a relatedapplication packet.

[0180] Stream block header 11 includes transport packet information 611,stream block information 612, sector data header information 613, andthe like, as shown in FIG. 9(b).

[0181] Transport packet information 611 in FIG. 9(b) is the same astransport packet information 611 in FIG. 9(c).

[0182] Stream block information 612 in FIG. 9(b) which recordsinformation that pertains to the entire stream block corresponds torecording time 622 (information of year, month, day, and time recordedon information storage medium 201), transport packet attribute 623(attribute information that pertains to a transport packet), streamblock size 624 (the data size of the corresponding stream block (e.g.,the data size can be expressed by the number of ECC blocks)), streamblock time difference 625, and the like in FIG. 9(c).

[0183] Taking FIG. 5(b) as an example, time range information in thecorresponding stream block is computed by [stream block timedifference]=[first time stamp value in stream block #2]−[value of timestamp a]. This [stream block time difference] corresponds to streamblock time difference 625.

[0184] Sector data header information 613 in FIG. 9(b) corresponds tofirst access point 626 and transport packet connection flag 627 in FIG.9(c). This sector data header information 613 includes informationsimilar to sector data 12 shown in FIG. 10 to be described later.

[0185] Transport packet information 611 in FIG. 9(c) includes the number631 of transport packets (the number of application packets), transportpacket mapping table 632, and the like, as shown in FIG. 9(d).

[0186] Note that the number of application packets in FIG. 9(d)corresponds to AP_Ns in FIG. 10(c) or FIG. 11 to be described later.

[0187] The number 631 of transport packets (application packets) in FIG.9(d) can include I-picture mapping table 641, B/P-picture mapping table642, and the like, as shown in FIG. 9(e).

[0188] Transport packet mapping table 632 in FIG. 9(d) can include videopacket mapping table 643, audio packet mapping table 644, program uniqueinformation mapping table 645, and the like.

[0189] Each mapping table (FIG. 9(e)) in transport packet mapping table632 has a bitmap format.

[0190] For example, when n transport packets (application packets) arerecorded in one stream block, the number 631 of transport packets (thenumber of application packets) in FIG. 9(d) assumes a value “n”.

[0191] Furthermore, each of mapping tables 643 to 645 consists of “n-bitdata”, and one bit is assigned to each of transport packets (applicationpackets) which line up in the stream block from the head side.

[0192]FIG. 10 is a view for explaining the internal structure of thesector data header shown in FIG. 1.

[0193] For example, sector data header 17 in FIG. 1(f) indicates datalayout information in data areas 22 and 23, and corresponds to sectordata header 12 (corresponding to an application header in FIG. 10(d)) inFIG. 10(a).

[0194] Sector data header 12 has an internal structure including firstaccess point 651 and transport packet connection flag 652, as shown inFIG. 10(b).

[0195] As shown in FIG. 10(d), one stream pack having a size of 2,048bytes, which is the same as the sector size, consists of a pack headerand stream PES header. The stream PES header contains an applicationpacket header corresponding to a portion of sector data header 12 inFIG. 10(a) or stream block header 11 in FIG. 9(a).

[0196] As shown in FIG. 10(c), this application packet header includes:

[0197] the version of the application packet header format;

[0198] the number AP_Ns of application packets (transport packets) whichstart within the stream pack of interest;

[0199] first application packet time stamp position FIRST_AP_OFFSETwhich describes the position of a time stamp of the first applicationpacket which starts within the stream pack of interest by a relativevalue from the first byte of that stream pack;

[0200] extension header information EXTENSION_HEADER_IFO indicating if aheader extension and/or stuffing byte are/is present; and

[0201] identifier SERVICE_ID of a service which generated the stream ofinterest.

[0202] FIRST_AP_OFFSET included in the application packet shown in FIG.10(d) corresponds to first access point 651 included in sector dataheader 12 in FIG. 10(a).

[0203] As shown in FIG. 1(g), transport packet d is recorded across twosectors. When the last time stamp or transport packet extends to thenext sector, transport packet connection flag 652 is set at “1”.

[0204] In the example shown in FIG. 1(g), the address in data area 22 ofthe time stamp head position located after transport packet d whichextends to the next sector is recorded in first access point 651(expressed in units of bits).

[0205] The first access point value of sector No. 1 (or itscorresponding stream pack) shown in FIG. 1(e) can be set to be largerthan the size of data area 22 (FIG. 1(f)) of sector No. 1. This valueindicates that the position of a time stamp corresponding to the nextpacket of a packet recorded in sector No. 1 is present in the next andsubsequent sectors.

[0206] In an embodiment of the present invention, since a value largerthan the size of data areas 21, 22, and 23 can be designated as thevalue of first access point 651, the time stamp head position can bedesignated for a packet having a size larger than the sector size (orstream pack size=2,048 bytes).

[0207] For example, assume that one packet is recorded across sector No.0 to sector No. 2 in the data structure shown in FIG. 1. Furthermore, atime stamp for that packet is recorded at the first position in dataarea 21 of sector No. 0, and a time stamp for the next packet is set atthe T-th bit position in a data area of sector No. 2. Such case will beexamined below.

[0208] In this case, the first access point value of sector No. 0 is“0”, that of sector No. 1 is “the size of data area 22 of sector No.1+T”, and that of sector No. 2 is “T”.

[0209]FIG. 11 is a view for explaining another example of time mapinformation 252 in an embodiment of the present invention.

[0210] This time map information 252 is an example different from timemap information 252 in FIGS. 3(h) and (i), and is table informationwhich describes the stream block sizes, stream block time differences,and the numbers (AP_Ns) of packets in units of stream blocks (firststream block, second stream block, . . . ).

[0211] Assume that the total number of transport packets (or the totalnumber AP_Ns of application packets) is designated to access (from theSTB side) a predetermined frame (picture) using time map information 252in FIG. 11. Then, the numbers of transport packets (AP_Ns) are summed up(by the disc apparatus side) in turn from the first stream block in FIG.11 to access a stream block at the time when the designated value hasbeen reached.

[0212]FIG. 12 is a view for explaining an example of the internalstructure of a sector (a stream pack including an application packet anda stream pack including a stuffing packet) that forms a stream block(SOBU).

[0213] Stream object (SOB) #A·298 in FIG. 12(d) is made up of aplurality of stream blocks #1, #2, . . . , as shown in FIGS. 12(c) and(e).

[0214] All stream blocks #1, #2, . . . are formed of stream object units(SOBU) each having a 2-ECC block size (=32 sectors=64 k bytes).

[0215] In this manner, even when stream block (SOBU) #2 is deleted, anECC block of stream block (SOBU) #1 is not influenced by this deletion.

[0216] First stream block (SOBU) #1 of SOB#A·298 is made up of sectorsNo. 0 to No. 31 (32 sectors/64 k bytes), as shown in FIG. 12(b).

[0217] Each sector of stream block (SOBU) #1 has a similar datastructure. For example, sector No. 0 has a data structure, as shown inFIG. 12(a).

[0218] More specifically, sector No. 0 consists of a 2,048-byte(2-Kbytes) stream pack, which is made up of a 14-byte pack header and2,034-byte stream PES packet.

[0219] The stream PES packet is comprised of a 6-byte PES header, 1-bytesubstream ID, and 2,027-byte stream data area.

[0220] The stream data area consists of a 9-byte application header,application header extension (option), stuffing byte (option), andapplication packet area.

[0221] The application packet area is made up of a group of applicationpackets each having an application time stamp (ATS) at its headposition.

[0222] For example, when a transport packet having a 188-byte size isstored as an application packet in the application packet area,approximately 10 application packets can be stored in the applicationpacket area.

[0223] In stream recording, an application that generates recordingcontents makes stuffing by itself to obviate the need for independentadjustment of the pack length. For this reason, in stream recording astream pack can always have a required length (e.g., 2,048 bytes).

[0224] The stuffing byte in FIG. 12(a) is used to maintain thepredetermined length (2,048 bytes) of a stream pack.

[0225] The pack header shown in FIG. 12(a) contains pack start codeinformation, SCR base information, SCR extension information, programmaximum rate information, marker bit, pack stuffing length information,and the like, although not shown.

[0226] The SCR base consists of 32 bits, and its 32nd bit is zero. Asthe program maximum rate, 10,08 Mbps are used.

[0227] The PES header and substream ID shown in FIG. 12(a) have thecontents shown in FIG. 8(c).

[0228] The application header in FIG. 12(a) includes versioninformation, the number AP_Ns of application packets, time stampposition FIRST_AP_OFFSET of the first application packet, extensionheader information EXTENSION_HEADER_IFO, service ID, and the like, asshown in FIG. 10(c).

[0229] Note that the version describes the version number of theapplication header format.

[0230] AP_NS in the application header describes the number ofapplication packets that start within the stream pack of interest. Ifthe stream pack of interest stores the first byte of ATS, it isdetermined that an application packet starts in this stream pack.

[0231] FIRST_AP_OFFSET describes the time stamp position of the firstapplication packet that starts within the stream packet of interest as arelative value (unit:byte) from the first byte in this stream packet. Ifno application packet starts within the stream packet, FIRST_AP_OFFSETdescribes “0”.

[0232] EXTENSION_HEADER_IFO describes whether or not an applicationheader extension and/or stuffing byte are/is present within the streampacket of interest.

[0233] If the contents of EXTENSION_HEADER_IFO are 00b, it indicatesthat neither the application header extension nor stuffing byte arepresent after the application header.

[0234] If the contents of EXTENSION_HEADER_IFO are 10b, it indicatesthat the application header extension is present after the applicationheader, but no stuffing byte is present.

[0235] If the contents of EXTENSION_HEADER_IFO are 11b, it indicatesthat the application header extension is present after the applicationheader, and the stuffing byte is also present after the applicationheader extension.

[0236] The contents of EXTENSION_HEADER_IFO are inhibited from assuming01b.

[0237] The stuffing byte (option) before the application packet area isactivated by “EXTENSION_HEADER_IFO= 11b”. In this manner, “packingparadox” can be prevented when the number of bytes in the applicationheader extension is contradictory to the number of application packetsthat can be stored in the application packet area.

[0238] SERVICE_ID describes the ID of a service that generates thestream. If this service is unknown, SERVICE_ID describes 0x0000.

[0239] The application packet area in FIG. 12(a) can have the sameconfiguration as that shown in the lower portion in FIG. 22 to bedescribed later (change “packet” in FIG. 22 to read “application packet”in FIG. 12).

[0240] That is, a partial application packet is recorded at the head ofthe application packet area, a plurality of pairs of application timestamps ATS and application packets are sequentially recorded after thepartial application packet, and a partial application packet is recordedat the end of the application packet area.

[0241] In other words, a partial application packet can be present atthe start position of the application packet area. At the end positionof the application packet area, a partial application packet or astuffing area with the reserved number of bytes can be present.

[0242] The application time stamp (ATS) allocated before eachapplication packet consists of 32 bits (4 bytes). This ATS can bedivided into two fields, i.e., a basic field and extended field. Thebasic field is called a 90-kHz unit value, and the extended fieldindicates a less significant value measured at 27 MHz.

[0243] In FIG. 12(a), the application header extension can be used tostore information which can differ between application packets. Suchinformation is not always required for all applications.

[0244] Therefore, the data field of the application header is defined tobe able to describe the presence of the application header extension asan option in the stream data area (in EXTENSION_HEADER_IFO mentionedabove).

[0245] Upon recording a stream, the first byte of application time stampATS of the first application packet must be aligned to the startposition of the application packet area in the first stream packet atthe beginning of stream object SOB.

[0246] On the other hand, as for the subsequent stream packet in theSOB, an application packet may be segmented (split) at the boundary ofneighboring stream packets.

[0247] The partial application packet shown in FIG. 22 or FIG. 23(f) and(g) to be described later indicates an application packet formed by thissegmentation (split).

[0248] The byte offset of the first application time stamp that startswithin the stream packet and the number of application packets whichstart within that stream packet are described in the application header.

[0249] With this format, stuffing before the first application timestamp and after the last application packet is automatically done in agiven stream packet.

[0250] That is, the automatic mechanism allows “the application to makestuffing by itself”. With this automatic stuffing, a stream packet canalways have a required length.

[0251] The application header extension (option) consists of a list ofentries. The list includes one entry having a 1-byte lengthcorresponding to each application packet that starts within the streampacket of interest. The bytes of these entries can be used to storeinformation which may differ in units of application packets.

[0252] Note that the 1-byte application header extension (option)describes 1-bit AU_START, 1-bit AU_END, and 2-bit COPYRIGHT.

[0253] When AU_START is set at “1”, it indicates that a relatedapplication packet includes a random access entry point (start of arandom access unit) within the stream.

[0254] When AU_END is set at “1”, it indicates that a relatedapplication packet is the last packet of the random access unit.

[0255] COPYRIGHT describes the state of the copyright of a relatedapplication packet.

[0256] The packet structure shown in FIG. 12(a) can be applied tosectors other than the last sector of SOB#A·298, but cannot always beapplied to the last sector.

[0257] For example, when the last sector of SOB#A·298 is sector No. 63in FIG. 12(f), and this sector consists of padding packet 40, as shownin FIG. 12(g), the contents of its padding area 38 (FIG. 12(h)) aredifferent from those in FIG. 12(a).

[0258] That is, as shown in FIG. 12(i), the stuffing packet as paddingpacket 40 consists of a 14-byte pack header, 6-byte PES header, 1-bytesubstream ID, 9-byte application header, and 2,018-byte applicationpacket area.

[0259] In a pack that includes the head of the stuffing packet, thisapplication packet area consists of 4-byte application time stamp ATSand 2,014-byte zero byte data (data having substantially no recordingcontents).

[0260] On the other hand, in a pack including the subsequent stuffingpacket, this application packet area consists of 2,018-byte zero bytedata (without ATS).

[0261] When recording is done at very low bit rate, the stuffing byte isrequired to ensure recovery (playback) of time map information (252 inFIG. 3(h); or MAPL in SOBI in FIG. 15 to be described later). Thestuffing packet in FIG. 12(i) is defined as a conceptual unit for thatpurpose.

[0262] The objective of this stuffing packet is achieved when each SOBUincludes at least one ATS value as well as the stuffing area.

[0263] The following conditions are attached to the stuffing packet:

[0264] One or a plurality of stuffing packets always start from theapplication packet area of a pack after a pack including actualapplication packet data; and

[0265] One or a plurality of stuffing packets consist of one 4-byte ATS,and zero byte data (following ATS) required to stuff the applicationdata area of the remaining pack of the SOBU of interest. Assuming thatSOBU_SIZ represents the number of sectors per SOBU, if 0≦n≦SOBU_SIZ−1,the total length of the stuffing packet is “4+2,014+n×2,018” bytes.

[0266] ATS of the stuffing packet is set as follows:

[0267] In an SOBU in which at least one pack includes actual applicationpacket data, ATS of the stuffing packet is set to be that of anapplication packet preceding the stuffing packet; and

[0268] In an SOBU that does not include any actual application packet,ATS of the stuffing packet is determined in accordance with the contentsof time map information or the like.

[0269] All packs each of which includes the stuffing packet or a portionof the stuffing packet are configured as follows:

[0270] SCR of the pack header is set to be the sum of SCR of thepreceding pack and “2,048×8 bits+ 10,08 Mbps”;

[0271] The PES packet header and substream ID are the same as those ofall other PES packets; and

[0272] In the application header (see FIG. 10(c) and 10(d)), AP_Ns=0,FIRST_AP_OFFSET=0, EXTENSION_HEADER_IFO=00b, and SERVICE_ID=0 (otherparameters in the application header are set at zero).

[0273]FIG. 13 is a view for explaining the internal data structure ofmanagement information (STREAM.IFO or SR_MANGR.IFO in FIG. 2) of thestreamer.

[0274] STREAM.IFO (SR_MANGR.IFO) 105 as management information(navigation data) shown in FIG. 2 or FIG. 3(e) includes streamerinformation STRI, as shown in FIG. 13.

[0275] This streamer information STRI is comprised of streamer videomanager information STR_VMGI, stream file information table SFIT,original PGC information ORG_PGCI (more generally, PGC informationPGCI#i), user-defined PGC information table UD_PGCIT, text data managerTXTDT_MG, and application private data manager APDT_MG, as shown in FIG.3(f) or FIG. 13.

[0276] Streamer video manager STR_VMGI includes video managerinformation management information VTSI_MAT that describes managementinformation which pertains to STRI and STR_VMGI, and the like, and aplay list search pointer table (PL_SRPT) that describes search pointersused to search for a play list in the stream, as shown in FIG. 13.

[0277] Note that the play list is a list of a portion of a program. Withthis play list, the user can define an arbitrary playback sequence (forthe contents of a program).

[0278] Stream file information table SFIT includes all navigation datathat directly pertain to the streamer operation. Details of stream fileinformation table SFIT will be explained later with reference to FIG.15.

[0279] Original PGC information ORG_PGCI is a portion that describesinformation which pertains to an original PGC (ORG_PGC). ORG_PGCindicates navigation data which describes a program set. ORG_PGC is achain of programs, and includes stream data recorded in a “.SRO” file(SR_TRANS.SRO 106 in FIG. 2) shown in FIG. 2 or FIG. 18 to be describedlater

[0280] Note that the program set indicates the entire recorded contents(all programs) of information storage medium 201. Upon playing back theprogram set, the same playback order as the recording order of programsis used except for a case wherein an arbitrary program has been edited,and the playback order of original recording has been changed. Thisprogram set corresponds to a data structure called an original PGC(ORG_PGC).

[0281] Also, a program is a logical unit of recorded contents, which isrecognized by the user or is defined by the user. A program in theprogram set is made up of one or more original cells. The program isdefined within only the original PGC.

[0282] Furthermore, a cell is a data structure indicating a portion of aprogram. A cell in the original PGC is called an “original cell”, and acell in a user-defined PGC (to be described later) is called a“user-defined cell”.

[0283] Each program in the program set consists of at least one originalcell. A portion of a program in each play list consists of at least oneuser-defined cell.

[0284] On the other hand, only a stream cell (SC) is defined in thestreamer. Each stream cell looks up a portion of the recorded bitstream.In an embodiment of the present invention, a “cell” means a “streamcell” unless otherwise specified.

[0285] Note that a program chain (PGC) is a generic unit. In an originalPGC, PGC indicates a chain of programs corresponding to a program set.On the other hand, in a user-defined PGC, PGC indicates a chain ofportions of programs corresponding to a play list.

[0286] A user-defined PGC indicating a chain of portions of programsincludes navigation data alone. A portion of each program looks upstream data belonging to the original PGC.

[0287] User-defined PGC information table UD_PGCIT in FIG. 13 caninclude user-defined PGC information table information UD_PGCITI, one ormore user-defined PGC search pointers UD_PGC_SRP#n, and one or morepieces of user-defined PGC information UD_PGCI#n.

[0288] User-defined PGC information table information UD_PGCITI includesUD_PGC_SRP_Ns indicating the number of user-defined PGC search pointersUD_PGC_SRP, and UD_PGCIT_EA indicating the end address of user-definedPGC information table UD_PGCIT (not shown).

[0289] The number of “UD_PGC_SRP”s indicated by UD_PGC_SRP_Ns is thesame as the number of pieces of user-defined PGC information (UD_PGCI),and is also the same as the number of user-defined PGCs (UD_PGC). Themaximum value of UD_PGC_SRP_Ns is “99”.

[0290] UD_PGCIT_EA describes the end address of UD_PGCIT of interest bythe relative number of bytes (F_RBN) from the first byte of thatUD_PGCIT.

[0291] Note that F_RBN indicates the relative number of bytes from thefirst byte of the defined field, and starts from zero.

[0292] PGCI#i that generally expresses original PGC information ORG_PGCIor user-defined PGC information UD_PGCI in user-defined PGC informationtable UD_PGCIT will be described later with reference to FIG. 14.

[0293] Text data manager TXTDT_MG in FIG. 13 is supplementary textinformation. This TXTDT_MG can be stored in the play list and programtogether with primary text information PRM_TXTI shown in FIG. 14.

[0294] Application private data manager APDT_MG in FIG. 13 can includeapplication private data manager general information APDT_GI, one ormore APDT search pointers APDT_SRP#n, and one or more APDT areas APDTA#n(not shown).

[0295] Note that application private data APDT is a conceptual area thatallows an application device connected to the streamer to storearbitrary non-real time information (more desired information inaddition to real-time stream data).

[0296]FIG. 14 is a view for explaining the internal data structure ofPGC Information (ORG_PGCI/UD_PGCIT in FIG. 3 or PGCI#i in FIG. 13).

[0297] PGC information PGCI#i in FIG. 14 generally expresses originalPGC information ORG_PGCI or user-defined PGC information UD_PGCI inuser-defined PGC information table UD_PGCIT in FIG. 13.

[0298] As shown in FIG. 14, PGC information PGCI#i is made up of PGCgeneral information PGC_GI, one or more pieces of program informationPGI#m, one or more stream cell information search pointers SCI_SRP#n,and one or more pieces of stream cell information SCI#n.

[0299] PGC general information PGC_GI includes the number PG_Ns ofprograms, and the number SCI_SRP_Ns of stream cell information searchpointers SCI_SRP.

[0300] Each program information PGI (e.g., PGI#1) includes program typePG_TY, the number C_Ns of cells in the program of interest, primary textinformation PRM_TXTI of the program of interest, and search pointernumber IT_TXT_SRPN of item text.

[0301] Note that program type PG_TY includes information indicating thestate of the program of interest. Especially, program type PG_TYincludes a flag indicating if that program is protected from an eraseerror, i.e., a protect flag.

[0302] When this protect flag is “0b”, the program of interest is notprotected; when it is “1b”, the program is protected.

[0303] The number C_Ns of cells indicates the number of cells in theprogram of interest. In all the programs and cells in a PGC, cells(tacitly) append themselves to each program in their ascending order.

[0304] For example, if program #1 in a given PGC has C_Ns=1, and program#2 has C_Ns=2, first stream cell information SCI of that PGC is appendedto program #1, and the second SCI and third SCI are appended to program#2.

[0305] Primary text information PRM_TXTI describes text informationhaving a single common character set (ISO/IEC646:1983 (ASCII code)) toallow use of information storage medium (DVD-RAM disc) 201 anywhere inthe world.

[0306] Item text search pointer number IT_TXT_SRPN describes a searchpointer number corresponding to item text (text data corresponding tothe program of interest) IT_TXT. If the program of interest has no itemtext, IT_TXT_SRPN is set at “0000h”.

[0307] Each stream cell information search pointer SCI_SRP (e.g.,SCI_SRP#1) includes SCI_SA indicating the start address of correspondingstream cell information SCI. This SCI_ SA is described as the relativenumber of bytes (F_RBN) from the first byte of PGCI.

[0308] Each stream cell information SCI (e.g., SCI#1) is made up ofstream cell general information SC_GI and one or more pieces of streamcell entry point information SC_EPI#n.

[0309] Stream cell general information SC_GI includes cell type C_TYincluding flag TE indicating a temporary erase (TE) state, the numberSC_EPI_Ns of pieces of entry point information of a stream cell, streamobject number SOB_N, stream cell start APAT (SC_S_APAT shown in FIG. 6and the like), stream cell end APAT (SC_E_APAT shown in FIG. 6 and thelike), erase start APAT (ERA_S_APAT shown in FIG. 6 and the like)indicating start APAT of a temporary erase cell if that cell is in thetemporary erase state (TE=01b), and erase end APAT (ERA_E_APAT shown inFIG. 6 and the like) indicating end APAT of a temporary erase cell ifthat cell is in the temporary erase state (TE=10b).

[0310] Cell type C_TY describes the type and temporary erase state ofthe stream cell of interest.

[0311] More specifically, cell type C_TY1=“010b” is described in thetype of all stream cells (with this C_TY1=“010b”, a stream cell can bedistinguished from other cells).

[0312] On the other hand, if flag TE is “00b”, it indicates that thecell of interest is in a normal state; if flag TE is “01b” or “10b”,that cell is in a temporary erase state.

[0313] Flag TE=“01b” indicates that the cell of interest (cell in thetemporary erase state) starts from a position after the firstapplication packet that starts within a SOBU, and comes to an end at aposition before the last application packet in that SOBU.

[0314] On the other hand, flag TE=“10b” indicates that the cell ofinterest (cell in the temporary erase state) includes at least one SOBUboundary (the first or last application packets starts within thatSOBU).

[0315] Note that a protect flag of a program and TE flag of a cell inthat program cannot be set at the same time. Therefore,

[0316] (a) none of cells in a program in the protect state can be set inthe temporary erase state; and

[0317] (b) a program including one or more cells in the temporary erasestate cannot be set in the protect state.

[0318] The number SC_EPI_Ns of pieces of entry point information of astream cell describes the number of pieces of stream cell entry pointinformation included in stream cell information SCI of interest.

[0319] Each stream cell entry point information SC_EPI (e.g., SC_EPI#1)in FIG. 14 includes two types (types A and B).

[0320] SC_EPI of type A includes entry point type EP_TY and entry pointapplication packet arrival time EP_APAT. Type A is set by entry pointtype EP_TY1= “00b”.

[0321] SC_EPI of type B includes primary text information PRM_TXTI inaddition to EP_TY and EP_APAT of type A. Type B is indicated by entrypoint type EP_TY1=“01b”.

[0322] As a tool for skipping a portion of the recorded contents in anarbitrary stream cell, an entry point can be used. All entry points canbe specified by application packet arrival times (APAT). This APAT canspecify the data output start position.

[0323] Stream object number SOB_N describes the number of an SOB thatthe cell of interest looks up.

[0324] Stream cell start APAT (SC_S_APAT) describes start APAT of thecell of interest.

[0325] Stream cell end APAT (SC_E_APAT) describes end APAT of the cellof interest.

[0326] Erase start APAT (ERA_S_APAT) describes an arrival time (APAT) ofthe first application packet that starts within the first SOBU, the headposition of which is included in a given temporary erase cell (TE fieldof its C_TY is “10b”) including at least one SOBU boundary, in thattemporary erase cell.

[0327] Erase end APAT (ERA_E_APAT) describes an arrival time (APAT) ofthe first application packet that starts within an SOBU including anapplication packet which immediately follows a temporary erase cell (TEfield of its C_TY is “10b”) including at least one SOBU boundary, inthat temporary erase cell.

[0328]FIG. 15 is a view for explaining the internal data structure ofthe stream file information table (SFIT).

[0329] As shown in FIG. 15, stream file information table SFIT is madeup of stream file information table information SFITI, one or morepieces of stream object stream information SOB_STI#n, and stream fileinformation SFI.

[0330] Stream file information table information SFITI consists of thenumber SFI_Ns of pieces of stream file information on informationstorage medium (DVD-RAM disc) 201, the number SOB_STI_Ns of pieces ofstream object stream information that follow SFITI, end address SFIT_EAof SFIT, and start address SFI_SA of SFI.

[0331] SFIT_EA describes the end address of SFIT by the relative numberof bytes (F_RBN) from the first byte of SFIT.

[0332] SFI_SA describes the start address of SFI by the relative numberof bytes (F_RBN) from the first byte of SFIT.

[0333] Stream object stream information SOB_STI includes three differentparameters. Each parameter can assume a value unique to individualbitstream recording. However, these parameter sets can have equal valuesin most bitstream recording. Therefore, SOB_STI is stored in a tableindependently from the table of stream object information (SOBI), andsome stream objects (SOB) are allowed to share identical SOB_STI (i.e.,point to identical SOB_STI). Therefore, the number of pieces of SOB_STIis generally larger than the number of SOBs.

[0334] Each stream object stream information SOB_STI (e.g., SOB_STI#1)in FIG. 15 includes application packet size AP_SIZ, the numberSERV_ID_Ns of service IDs, service ID (SERV_IDs), and application packetdevice unit ID (AP_DEV_UID).

[0335] AP_SIZ describes the application packet size by the byte lengthof a packet in a bitstream transferred from an application device to thestreamer.

[0336] In the DVD streamer, the application packet size is constant ineach bitstream recording. For this reason, if the application packetsize changes in each recording free from any interrupt, the currentstream object (current SOB) comes to an end there, and a new streamobject (new SOB) starts with new AP_SIZ. In this case, the current andnew SOBs belong to an identical program in original PGC information(ORG_PGCI).

[0337] SERV_ID_Ns describes the number of service IDS included in thesubsequent parameter.

[0338] SERV_IDS describes a list of service IDS in an arbitrary order.

[0339] AP_DEV_UID describes a unique device ID unique to an applicationdevice that supplies the recorded bitstream.

[0340] As shown in FIG. 15, stream file information SFI is comprised ofstream file general information SF_GI, one or more stream objectinformation (SOB information) search pointers (SOB_SRP) #n, and one ormore pieces of SOB information (SOBI) #n.

[0341] Stream file general information SF_GI includes the number SOBI_Nsof pieces of SOBI, sector size SOBU_SIZ per SOBU, and MTU_SHFT as a kindof time map information.

[0342] SOBU_SIZ describes the SOBU size using the number of sectors, andthis size is constant to be 32 (32 sectors=64 k bytes). This means thatthe first entry is associated with an application packet included in thefirst 32 sectors of an SOB. Likewise, the second entry is associatedwith an application packet included in the next 32 sectors. The sameapplies to the third and subsequent entries.

[0343] Each SOB information search pointer (e.g., SOBI_SRP#1) includesstart address SOBI_SA of SOBI. This SOBI_SA describes the start addressof the associated SOBI using the relative number of bytes (F_RBN) fromthe first byte of stream file information SFI.

[0344] Each SOB information (e.g., SOBI#1) is made up of stream objectgeneral information SOB_GI, time map information MAPL, and access unitdata AUD (option).

[0345] Stream object general information SOB_GI includes stream objecttype SOB_TY, stream object recording time SOB_REC_TM, stream objectstream information number SOB_STI_N, access unit data flag AUD_FLAGS,stream object start application packet arrival time SOB_S_APAT, streamobject end application packet arrival time SOB_E_APAT, start streamobject unit SOB_S_SOBU of the stream object of interest, and the numberMAPL_ENT_Ns of entries in time map information.

[0346] Stream object type SOB_TY is a field that describes bitsindicating the temporary erase state (TE state) and/or bits of the copygeneration management system.

[0347] Stream object recording time SOB_REC_TM describes the recordingtime of the associated stream object (SOB).

[0348] Stream object stream information number SOB_STI_N describes anindex of valid SOB_STI for the stream object of interest.

[0349] Access unit data flag AUD_FLAGS describes whether or not accessunit data (AUD) is present for the stream object of interest, and thetype of access unit data if it is present.

[0350] If access unit data (AUD) is present, AUD_FLAGS describes someproperties of AUD.

[0351] The access unit data (AUD) itself consists of access unit generalinformation AU_GI, access unit end map AUEM, and playback time stamplist PTSL, as shown in FIG. 15.

[0352] Access unit general information AU_GI includes AU_Ns indicatingthe number of access units described in correspondence with the SOB ofinterest, and access unit start map AUSM indicating an SOBU that belongsto the SOB of interest and includes an access unit.

[0353] Access unit end map AUEM is a bit array having the same length asthat of AUSM (if it is present), and indicates an SOBU that includes theterminal end of a bitstream segment appended to the access unit of theSOB of interest.

[0354] Playback time stamp list PTSL is a list of playback time stampsof all access units that belong to the SOB of interest. One PTSL elementincluded in this list includes a playback time stamp (PTS) of thecorresponding access unit.

[0355] Note that the access unit (AU) indicates an arbitrary single,continuous portion of the recorded bitstream, and is suitable forindividual playback. For example, in an audio/video bitstream, an accessunit corresponds to I-picture of MPEG.

[0356] The contents of SOB_GI will be explained again.

[0357] AUD_FLAGS includes flag RTAU_FLG, flag AUD_FLG, flag AUEM_FLG,and flag PTSL_FLG.

[0358] When flag RTAU_FLG is 0b, it indicates that no access unit flagis present in real-time data of the SOB of interest.

[0359] When flag RTAU_FLG is 1b, it indicates that AU flags (AU_START,AU_END) described in the application header extension shown in FIG. 9(a)or FIG. 12(a) can be present in real-time data of the SOB of interest.This state is also allowed when AUD_FLG (to be described below) is 0b.

[0360] When flag AUD_FLG is 0b, it indicates that no access unit data(AUD) is present for the SOB of interest.

[0361] When flag AUD_FLG is 1b, it indicates that access unit data (AUD)can be present for the SOB of interest.

[0362] When flag AUEM_FLG is 0b, it indicates that no AUEM is present inthe SOB of interest.

[0363] When flag AUEM_FLG is 1b, it indicates that AUEM is present inthe SOB of interest.

[0364] When flag PTSL_FLG is 0b, it indicates that no PTSL is present inthe SOB of interest.

[0365] When flag PTSL_FLG is 1b, it indicates that PTSL is present inthe SOB of interest.

[0366] SOB_S_APAT describes the start application packet arrival time ofa stream object. That is, SOB_S_APAT indicates the arrival time of thefirst application packet that belongs to the SOB of interest.

[0367] This packet arrival time (PAT) is divided into two fields, i.e.,a basic field and extended field. The basic field is called a 90-kHzunit value, and the extended field indicates a less significant valuemeasured at 27 MHz.

[0368] SOB_E_APAT describes the end application packet arrival time of astream object. That is, SOB_E_APAT indicates the arrival time of thelast application packet that belongs to the SOB of interest.

[0369] SOB_S_SOBU describes the start stream object unit of the streamobject of interest. That is, SOB_S_SOBU indicates an SOBU including thestart portion of the start application packet of the stream object.

[0370] MAPL_ENT_Ns describes the number of entries in time mapinformation (MAPL) that follows SOBI_GI.

[0371] Time map information MAPL has contents corresponding to time mapinformation 252 shown in FIG. 3(h).

[0372] One of relevancies between the contents of FIGS. 13 and 15 issummarized as follows:

[0373] Streamer information STRI included in management information 105contains stream file information table SFIT that manages stream objectSOB which forms the contents of stream data. This SFIT includes streamobject information SOBI that manages SOB. This SOBI includes access unitgeneral information AU_GI including management information (access unitstart map AUSM), and management information (PTSL).

[0374] Note that the management information (ATS or AUSM) containsinformation used upon transferring stream data, and the managementinformation (PTS or SC_S_APAT) contains information used when the streamdata is displayed.

[0375]FIG. 16 is a view exemplifying the correspondence between theaccess unit start map (AUSM; see FIG. 15) and stream object unit (SOBU;see FIG. 1, FIGS. 4 to 6, and FIG. 12).

[0376] As shown in FIG. 16, bit “1” of AUSM indicates that the accessunit (AU) is included in the corresponding SOBU.

[0377] Assume that AUSM_pos(i) represents the i-th (1≦i≦AU_Ns) bitposition where a bit is set in AUSM. Then, the position of access unitAU is as follows.

[0378] (1) If SOBU#i indicated by AUSM_pos(i) contains one or more startAUs (described using AU_START and AU_END marks in a stream (ifavailable)), AUSM_pos(i) is assigned to the first AU that starts withinSOBU#i. Note that SOBU#i is laid out in SOBUs described usingAUSM_pos(i) and AUEM_pos(i) (if AUEM is available).

[0379] (2) AU comes to an end at the AU_END mark that appears firstafter this AU starts, and comes to an end in the last SOBU indicated bythe assigned AUEM element (if AUEM is available).

[0380] In any access unit data, two or more accessible access unitscannot be described per SOBU in an SOB.

[0381]FIG. 17 is a view exemplifying the correspondence between theaccess unit start map (AUSM; see FIG. 15) and access unit end map (AUEM;see FIG. 15), and stream object unit (SOBU; see FIGS. 2, 4, and 11).

[0382] AUEM is a bit array having the same length as the AUSM (ifavailable). The bits of AUEM indicate a SOBU that includes the end of abitstream segment appended to the access unit of the SOB of interest.

[0383] The number of bits set in AUEM matches that set in AUSM. That is,the set bits in AUSM have those set in AUEM in correspondence with eachother.

[0384] Assume that AUSM_pos(i) represents the i-th (1≦i≦AU_Ns) bitposition where a bit is set in AUSM, and AUEM_pos(i) the i-th(1≦i≦AU_Ns) bit position where a bit is set in AUEM. In this case, thefollowing relations hold:

[0385] (1) 1≦AUSM_pos(i)≦AUEM_pos(i)≦MAPL_ENT_Ns;

[0386] (2) AUSM_pos(i+1)>AUEM_pos(i);

[0387] (3) If i== AU_Ns or AUSM_pos(i+1)>1 AUEM_pos(i), AU#i comes to anend in SOBU#[AUEM_pos(i)] (1≦i≦AU_Ns); and

[0388] (4) If AUSM_pos(i+1)==1+ AUEM_pos(i), AU#i comes to an end inSOBU#[AUEM_pos(i)]. Or it comes to an end at the position ofSOBU#[1+AUEM_pos(i)]== SOBU#[AUSM_pos(i+1)]. That is, AU#i comes to anend at the beginning of AU#i+1 in SOBU (1≦i≦AU_Ns).

[0389]FIG. 18 is a view showing an example of the relationship definedbetween cells designated by an original or user-defined PGC, and SOBUscorresponding to these cells via time map information.

[0390] A user-defined PGC does not contain its own SOB, but looks up anSOB in an original PGC. Therefore, the user-defined PGC can be describedusing only PGC information. This means that an arbitrary playbacksequence can be implemented without modifying SOB data.

[0391] The user-defined PGC does not contain any program, and is made upof a chain of cells corresponding to portions of programs in theoriginal PGC.

[0392]FIG. 18 shows an example of such user-defined PGC. In thisexample, user-defined PGC#n is formed so that a cell in the PGC looks upan SOB in an original PGC.

[0393] Referring to FIG. 18, PGC#n has four cells #1 to #4. Of thesecells, two cells look up SOB#1, and the remaining two cells look upSOB#2.

[0394] The solid arrows from cells in the user-defined PGC to theoriginal PGC (time map information of an SOBI) indicate the playbackperiods of those cells. The cell playback order in the user-defined PGCbecomes quite different from that in the original PGC.

[0395] Playback of an arbitrary SOB and its SOBUs is specified by startAPAT (S_APAT) and end APAT (E_APAT) in FIG. 18.

[0396] S_APAT of the SOB or SOBU is defined in association with a timestamp recorded in the payload (see FIG. 1(h), FIG. 22, and FIG. 23) of astream pack of the SOB of interest.

[0397] During SOB recording, each incoming application packet isappended with a time stamp by the local clock reference in the streamer.This is the application packet arrival time (APAT).

[0398] APAT of the start application packet of the SOB is stored asSOB_S_APAT. Four least significant bytes of all APATS are fixed inadvance for a corresponding application packet in a “_.SRO” file.

[0399] In order to play back data of the SOB or SOBU, the internalreference clock of the streamer is set at an SCR value, and clocks arethen automatically counted. This SCR value is described in the firststream pack (pack header) from which playback begins. Based on theclocks, all subsequent application packets are played back and outputfrom the SOB or SOBU.

[0400] When an arbitrary stream cell (SC) defines stream cell start APAT(SC_S_APAT) that has an arbitrary value between SOB_S_APAT andSOB_E_APAT of an SOB that SC points to, an address used to find out anSOBU that includes an application packet with a desired APAT isrequired.

[0401] The number of stream packs per SOBU is constant, but theintervals of arrival times captured by SOBUs are flexible. Therefore,each SOB has time map information (MAPL) that describes the arrival timeintervals of its SOBUs. That is, the address system implemented by timemap information (MAPL) converts arbitrary APAT into a relative logicalblock address in the file to point to an SOBU that can find out adesired application packet.

[0402]FIG. 19 is a block diagram for explaining the arrangement of astream data recording/playback system (optical disc device/streamer, STBunit) according to an embodiment of the present invention. Thisembodiment assumes as information storage medium 201 arecordable/reproducible optical disc such as a DVD-RAM disc or the like.

[0403] The internal structure of the stream data recording/playbackapparatus according to an embodiment of the present invention will bedescribed below using FIG. 19.

[0404] This stream data recording/playback apparatus comprises opticaldisc device (or optical disc drive) 415, STB unit (or STB device) 416,and their peripheral devices.

[0405] The peripheral devices include video mixing unit 405, framememory 406, external loudspeaker 433, personal computer (PC) 435,monitor TV 437, D/A converters 432 and 436, I/F units 431 and 434, andthe like.

[0406] Optical disc device 415 comprises recording/playback unit 409including a disc drive, data processor (to be abbreviated as D-PROhereinafter) 410 for processing stream data to recording/playback unit409 (or stream data from recording/playback unit 409), temporary storage411 for temporarily storing stream data that overflows from D-PRO 410,and optical disc device controller 412 for controlling operations ofrecording/playback unit 409 and D-PRO 410.

[0407] Optical disc device 415 further comprises data transfer interface414 for receiving stream data sent from STB unit 416 via IEEE1394 or thelike (or sending stream data to STB unit 416 via IEEE1394 or the like),and formatter/deformatter 413 for converting the stream data received bydata transfer interface 414 into a signal format that can be recorded oninformation storage medium (RAM disc) 201 (or converting the stream dataplayed back from medium 201 into a signal format for, e.g., IEEE1394 orthe like).

[0408] More specifically, the IEEE1394 reception side of data transferinterface 414 reads the time from the start of stream data transfer onthe basis of the time count value of reference clock generator (systemtime counter STC) 440.

[0409] Based on the time information, delimiter information for dividingstream data in units of stream blocks (or in units of SOBUS) isgenerated, and cell division information, program division information,and PGC division information are generated in correspondence with thisdelimiter information.

[0410] Formatter/deformatter 413 converts the stream data sent from STBunit 416 into a stream pack sequence (see FIG. 12(a), FIG. 23(h), etc.),and inputs the converted stream pack sequence to D-PRO 410. Each of theinput stream packs has a constant size of 2,048 bytes, which is equal tothe sector size. D-PRO 410 combines the input stream packs in units of16 sectors to form ECC blocks, and sends the ECC blocks torecording/playback unit 409.

[0411] When recording/playback unit 409 is not ready to record data onmedium 201, D-PRO 410 transfers recording data to temporary storage 411to temporarily save them therein, and waits until recording/playbackunit 409 is ready to record data.

[0412] When recording/playback unit 409 is ready to record data, D-PRO410 transfers data saved in temporary storage 411 to recording/playbackunit 409. In this manner, recording on medium 201 is started. Uponcompletion of recording of data saved in temporary storage 411, thesubsequent data are seamlessly transferred from formatter/deformatter413 to D-PRO 410.

[0413] Assume that a large-size memory is used as temporary storage 411so as to store recording data for several minutes or more by high-speedaccess.

[0414] Note that time stamp information appended to the recordingbitstream via formatter/deformatter 413 can be obtained from referenceclock generator (STC) 440.

[0415] On the other hand, time stamp information (SCR) extracted fromthe playback bitstream via formatter/deformatter 413 can be set in STC440.

[0416] Each pack header in the stream data recorded on informationstorage medium 201 records a reference clock (system clock referenceSCR). When the stream data (SOB or SOBU) recorded on this medium 201 isplayed back, reference clock generator (STC) 440 is adjusted to thereference clock (SCR) played back from medium 201 (the SCR value is setin STC 440).

[0417] That is, in order to play back SOB or SOBU data, the referenceclock (STC 440) in the streamer (optical disc device 415) is adjusted tosystem clock reference SCR described in the first stream pack from whichplayback starts. After that, STC 440 is automatically counted up.

[0418] STB unit 416 comprises demodulator 422 for demodulating thecontents of a digital broadcast wave received by satellite antenna 421,and providing demodulated data (stream data) that multiplexes one ormore programs, and reception information selector 423 for selectinginformation of a specific program (of user's choice) (taking FIG. 23 tobe described later as an example, a transport packet of program 2) fromdata demodulated by demodulator 422.

[0419] When the information (transport packet) of the specific programselected by reception information selector 423 is to be recorded oninformation storage medium 201, selector 423 sends stream datacontaining only the transport packet of the specific program to datatransfer interface 414 of optical disc device 415 by IEEE1394 transfervia data transfer interface 420 in accordance with an instruction fromSTB controller 404.

[0420] When the user merely reviews the information (transport packet)of the specific program selected by reception information selector 423without recording it, selector 423 sends stream data containing only thetransport packet of the specific program to multiplexed informationdemultiplexer 425 of decoder unit 402 in accordance with an instructionfrom STB controller 404.

[0421] On the other hand, when a program recorded on information storagemedium 201 is to be played back, stream data sent from optical discdevice 415 to STB unit 416 via an IEEE1394 serial bus is sent tomultiplexed information demultiplexer 425 of decoder unit 402 viaselector 423.

[0422] Multiplexed information demultiplexer 425 classifies variouspackets (video packets, audio packets, and sub-picture packets)contained in the stream data sent from selector 423 on internal memory426 on the basis of their IDs. Then, demultiplexer 425 distributes theclassified packets to corresponding decoders (video decoder 428,sub-picture decoder 429, and audio decoder 430).

[0423] Video decoder 428 decodes (MPEG-encoded) video packets sent frommultiplexed information demultiplexer 425 to generate moving picturedata. Video decoder 428 incorporates representative image (thumbnail)generator 439 to provide a function of generating a reduced-scalepicture (thumbnail picture) that represents the recorded contents fromI-picture in MPEG video data in such case.

[0424] Moving picture data (and/or the representative image generated bygenerator 439) decoded by video decoder 428, sub-picture data(information of superimposed dialogs, menus, and the like) decoded bysub-picture decoder 429, and audio data decoded by audio decoder 430 aresent to video mixing unit 405 via video processor 438.

[0425] Video mixing unit 405 generates a digital video by superposingthe superimposed dialogs and the like on the moving picture using framememory 406. This digital video is converted into an analog video via D/Aconverter 436, and the analog video is sent to monitor TV 437.

[0426] Also, the digital video from video mixing unit 405 is fetched asneeded by personal computer 435 via I/F unit 434 and a signal line suchas IEEE1394 or the like.

[0427] On the other hand, digital audio information decoded by audiodecoder 430 is sent to external loudspeaker 433 via D/A converter 432and an audio amplifier (not shown). Also, decoded audio information isdigitally output to an external device via I/F unit 431.

[0428] Note that the operation timing in STB unit 416 is determined byclocks from system time counter (STC) 424.

[0429] The aforementioned instructions and the like from STB controller404 (operation control of the internal components of STB unit 416) areexecuted by a control program stored in program memory 404 a. In thiscase, work memory 407 is used as needed in the control process of STBcontroller 404.

[0430] The internal operation timings of STB unit 416 including STBcontroller 404 and decoder unit 402 can be restricted by clocks from STCunit 424. By synchronizing STC 440 of optical disc device 415 with STCunit 424 of STB unit 416, the operation timings of the overall streamersystem including optical disc device 415 and STB unit 416 can berestricted.

[0431] As a method of synchronizing STC 440 with STC unit 424, a methodof setting STC 440 and STC unit 424 using a reference clock (SCR) instream data exchanged between data transfer interfaces 414 and 420 isavailable.

[0432] The device arrangement in STB unit 416 shown in FIG. 19 can befunctionally divided/categorized into a “reception time managementmodule”, “stream data content analysis module”, “stream data transfermodule”, and “time related information generation module”.

[0433] Note that the “reception time management module” is comprised ofdemodulator (demodulation unit) 422, reception information selector 423,multiplexed information demultiplexer 425, STB controller 404, and thelike. The “reception time management module” receives digital TVbroadcast via satellite antenna 421, and records reception times inunits of transport packets in the received broadcast information.

[0434] The “stream data content analysis module” is comprised ofmultiplexed information demultiplexer 425, STB controller 404, and thelike. This “stream data content analysis module” analyzes the contentsof the received stream data, and extracts I-, B-, and P-picturepositions and/or PTS values.

[0435] The “stream data transfer module” is comprised of multiplexedinformation demultiplexer 425, reception information selector 423, STBcontroller 404, data transfer interface 420, and the like. This “streamdata transfer module” transfers the stream data to optical disc device415 while holding differential reception time intervals in units oftransport packets.

[0436] The “time related information generation module” is comprised ofmultiplexed information demultiplexer 425, STB controller 404, datatransfer interface 420, and the like. The “time related informationgeneration module” generates relationship information between receptiontime (time stamp) information recorded by the “reception time managementmodule” and display time information (PTS value and/or the number offields) extracted by the “stream data content analysis module”.

[0437]FIG. 20 is a view for explaining the time relationship table thatindicates the relationship between the display time and data transfertime in an embodiment of the present invention. A basic feature of thisinvention will be explained below using FIG. 20.

[0438] The NTSC scheme as one of TV display schemes displays 30images/pictures (frames) on a TV monitor screen as a video signal. Sincea normal TV uses interlaced scan, an image is scanned every other linesof all scan lines for one image, and is then scanned remaining, everyother lines to fill gaps of the immediately preceding image, thusdisplaying one image (picture). The image to be displayed every otherlines is called a field.

[0439] The NTSC scheme displays 30 frames/60 fields per sec. The NTSCscheme is a display scheme mainly adopted in Japan and USA. By contrast,the PAL scheme adopted in Europe displays 25 frames/50 fields per sec.

[0440]FIG. 20(a) is a view showing 30 changing images/pictures (frames)per sec which are aligned along the display time (presentation time; orplayback time) 1.

[0441] As information that expresses display time (playback time) 1 ofan image/picture,

[0442] (a) a method of expressing time by “the number of differentialfields from a specific image (picture)”; and

[0443] (b) a method of expressing time by “PTS (presentation time stamp;or playback time stamp)” are available.

[0444] PTS can be used in the method of expressing the display time bythe value of a counter which always increments (the counter valueincreases in unitary increments) using reference clocks of 27 MHz and/or90 kHz. For example, the value of a counter when each image/picture(frame) is indicated by a counter which increments using referenceclocks of 27 MHz (or 90 kHz) is used as the PTS value.

[0445] In reception signal information in digital TV, picture headerinformation 41 (see FIG. 1(j)) contains PTS values in units of pictures.

[0446] In FIG. 20(a), the display time of I-picture a is represented byPTS No. 1, and the display times of I-pictures i and q are representedby PTS No. 2 and PTS No. 3.

[0447] Assume that the user instructs to display an image (picture) xxhours yy minutes zz seconds after display of I-picture a. Then, thedesignated time interval (xx hours yy minutes zz seconds after) isconverted into a count value of 27 MHz and/or 90 kHz. The sum of thisconverted value and the PTS value (PTS No. 1) of display of I-picture ais then computed to reach the “image (picture) to be displayed”designated by the user.

[0448] Since stream data is recorded on information storage medium 201while being appended with time stamps in units of transport packets, asshown in FIG. 1(g) and the like, time management for the stream data isdone using this time stamp information.

[0449] However, since this time stamp information is invisible to theuser, the user designates the image (picture) of his or her choice usingdisplay time (playback time) 1.

[0450] In this case, information indicating the relationship between thetime stamp information used to manage the stream data, and display time(playback time) 1 information that the user can designate is required.The information indicating this relationship is time relationship table2 shown in FIG. 20(b) (or playback time stamp list PTSL in FIG. 15).

[0451] As exemplified in FIG. 20(b), time relationship table 2 describescorresponding data transfer time information (I-picture transfer starttime 4), data transfer time information (I-picture transfer end time 5),and the total number 10 of packets from the beginning of a cell to atarget I-picture in units of PTS values (PTS No. 1, PTS No. 2, PTS No.3, . . . ).

[0452] For example, as for I-picture a of PTS No. 1, time stamp (ATS) #1in the row of data transfer time information (I-picture transfer starttime 4) corresponds to time stamp (ATS) #1 of head-side packet (AP) #1of I-picture a information 7 in FIG. 2(c), and time stamp (ATS) #2 inthe row of data transfer time information (I-picture transfer end time5) corresponds to time stamp (ATS) #2 of trailing-side packet (AP) ofI-picture a information 7 in FIG. 2(c). In this case, since I-picture ais the first one, the total number 10 of packets for I-picture a of PTSNo. 1 is “1”, as shown in FIG. 20(b).

[0453] Likewise, as for I-picture i of PTS No. 2, time stamp (ATS) #3 inthe row of data transfer time information (I-picture transfer start time4) corresponds to time stamp (ATS) #3 of head-side packet (AP) #1 ofI-picture i information 8 in FIG. 2(c), and time stamp (ATS) #4 in therow of data transfer time information (I-picture transfer end time 5)corresponds to time stamp (ATS) #4 of trailing-side packet (AP) ofI-picture i information 8 in FIG. 2(c). In this case, since I-picture iappears 85,100 images after the first I-picture a, the total number 10of packets for I-picture i of PTS No. 2 is “85101”, as shown in FIG.20(b). The same applies to PTS No. 3 and the subsequent PTS values.

[0454] A characteristic feature of the present invention lies in thattime relationship table 2 shown in FIG. 20(b) is recorded in an areawhere management information (SFIT in FIG. 15) that pertains to streamdata (STREAM.VRO 106 in FIG. 1(c), FIG. 20(c), and the like) isrecorded, and the user can designate an image position in units ofpictures using this time relationship table.

[0455] The correspondence between time relationship table 2 and playbacktime stamp list PTSL shown in FIG. 15 will be explained below.

[0456] If ATS represents a time stamp shown in FIG. 1(g) and the like,the PTS value included in playback time stamp list PTSL in FIG. 15 andATS have the following relationship:

[0457] (1) a cell looks up a portion of the recorded bitstream;

[0458] (2) AU (normally, I-picture) is a continuous portion of therecorded bitstream (AU corresponds to a portion of a cell);

[0459] (3) an SOBU that includes the AU (I-picture corresponding to aportion of a cell) is indicated by access unit start map AUSM in FIG. 15(see FIG. 16);

[0460] (4) the PTS value is the playback time of the corresponding AU(display time; or presentation time PTM) (the PTS value corresponding tothe AU corresponds to a portion of a cell in association with theplayback time);

[0461] (5) cell start APAT (SC_S_APAT) is the arrival time of atransport packet or application packet of the cell of interest(SC_S_APAT corresponds to the PTS value in association with the playbacktime);

[0462] (6) transport packet or application packet AP includes time stampATS at its head position (see FIG. 22, FIG. 29(g), etc.);

[0463] (7) the PTS value is included in PTSL (see FIG. 15); and

[0464] (8) from (3) to (7), the PTS value included in PTSL correspondsto ATS through the mediation of AUSM, SC_S_APAT, and the like.

[0465] Therefore, playback time stamp list PTSL can be “timerelationship table (FIG. 20(b))” including information (PTS value)indicating the relationship (one which pertains to the playback time)between the start time (SC_S_APAT) of AU (I-picture) and time stamp ATSof a packet included in the bitstream.

[0466] Or PTSL (time relationship table) can be information indicatingthe correspondence between the PTS value and ATS.

[0467] Display of B- or P-picture must be started from display (decode)of I-picture. For this reason, time relationship table 2 shown in FIG.20(b) represents a list of display time information corresponding to atime stamp at the I-picture position.

[0468] In this case, as the display time information, “PTS information(PTS value)”, “the number of differential fields from a specificreference image (picture)”, “date & time information”, and the like canbe used.

[0469] Note that the differential information between I-pictures (e.g.,information indicating the number of fields inserted between I-pictures)may be used as the time display information in place of the absolutevalue display shown in FIG. 20(b). (A time relationship table that usesthe number of fields will be explained later with reference to FIG. 28).

[0470] In FIG. 20(b), “PTS information” is used as the display timeinformation. However, the embodiment of the present invention thatallows various modifications is not limited to this specific method, and“the number of differential fields from a specific reference image(picture)”, “date & time information”, or the like can be used instead.

[0471] Time relationship table 2 shown in FIG. 20(b) records not onlythe values of transfer start time 4 in units of I-pictures in a list astime stamps (ATS) #1, #3, and #5, but also the values of transfer endtime 5 in units of I-pictures as time stamps (ATS) #2, #4, and #6.

[0472] For this reason, upon making special playback such as fastforward(FF) playback, fast reverse (FR) playback, or the like, the transportpacket position (or application packet position) of I-picture to beplayed back can be designated like “from time stamp (ATS) #1 to #2”,“from time stamp (ATS) #3 to #4”, “from time stamp (ATS) #5 to #6”, andso forth. By so doing, only I-picture information (or access unit AUinformation) can be played back from information storage medium 201, sothat the played back information is decoded and displayed.

[0473] In the embodiment shown in FIG. 20(a), the display start pictureposition (the position of B-picture i) of an original cell (see FIG. 4)is used as a reference. The difference between the PTS value (PTS No. 5)of the display start picture of this original cell and that (PTS No. 1)of I-picture a immediately before that picture is PTS offset 9. This PTSoffset value 9 is recorded in original cell information 272, as shown inFIG. 3(h).

[0474] More specifically, as shown in FIG. 20(a), assume that thedisplay start picture of the original cell is B-picture f, and the PTSvalue at that time is PTS No. 5. If the display time of I-picture aimmediately before that picture is PTS No. 1, the value of PTS offset 9is given by “PTS No. 5−PTS No. 1”.

[0475] When the user designates a specific image (specific pictureframe), he or she normally designates it using the differential displaytime from the display start position of the original cell. By convertingthis differential display time into a counter value of 27 MHz and/or 90kHz, the PTS value of the image (picture frame) designated by the usercan be computed.

[0476] As shown in FIG. 20(b), time relationship table 2 records a PTSvalue list in units of I-pictures. By searching for the PTS value of anI-picture position, which is smaller than and closest to the computedPTS value with reference to this table, and designating the time stamp(ATS) value of corresponding I-picture transfer start time 4 there,access to information storage medium 201 is started.

[0477] As shown in FIG. 20(b), time relationship table 2 also recordsthe total number 10 of transport packets (access position information)from the head position of the original cell to the correspondingI-picture parallel to time stamps.

[0478] Hence, according to the embodiment shown in FIG. 20, a desiredstream data position can be also be accessed by designating the numberof transport packets from the head position of the original cell (or thenumber AP_Ns of application packets) in place of the time stamp (ATS).

[0479] When stream data (STREAM.VRO) 106 shown in FIG. 20(c) is recordedon information storage medium 201 shown in FIG. 3 and the like, thecontents (SOB or SOBU) of stream data 106 are recorded on a data area(STREAM.VRO/SR_TRANS.SRO) of medium 201 in predetermined data recordingunits (transport packets or application packets). In this case,management information (STRI) that pertains to stream data 106 is alsorecorded on a management area (STREAM.IFO/SR_MANGR.IFO) of medium 201.

[0480] This management information (STRI) records first managementinformation (ATS corresponding to the I-picture transfer start time; orAUSM) used to access stream data 106 (access I-picture information oraccess unit AU); and third management information (time relationshiptable; or PTSL) which is different from the first management information(AUSM) and indicates the relationship between the first managementinformation and second management information (PTS; or SC_S_APAT) usedto access the first management information and the stream data.

[0481] Stream data 106 is a bitstream compressed based on MPEG, and thesecond management information corresponds to the playback time (PTS) ofthe stream data.

[0482]FIG. 21 is a view for explaining the relationship between thedisplay time and data transfer time in an embodiment of the presentinvention.

[0483] The layout relationship between the recording positions ofpicture information 6010 to 6030 and stream blocks (SOBUs) inassociation with the data structure in stream data (STREAM.VRO 106 inFIGS. 1, 2, etc.) recorded on information storage medium 201 will beexplained using FIG. 21.

[0484] In this embodiment, stream data is recorded in units of streamblocks (SOBUs), and access to a predetermined image (picture) isdesignated using time stamp information.

[0485] When STB unit 416 in FIG. 19 designates a time stamp value as theplayback start position, information used to compute a stream block(SOBU) corresponding to the designated time stamp value is time mapinformation 252 in FIG. 3(h) (or time map information MAPL in FIG. 15 ortime map information in FIG. 18).

[0486] In the example in FIG. 3(h), time map information 252 is recordedas a portion of stream object information (SOBI) 242 in STREAM.IFO 105as the management information recording area for stream data. In theexample in FIG. 15 as well, time map information MAPL is recorded as aportion of SOBI.

[0487] Time map information 252 shown in FIG. 3(i) records only timestamp differential time information of each stream block. In this case,the values of time differences 263 and 265 of stream blocks in time mapinformation 252 are summed up in each of stream object information(SOBI) 242 or 243. Comparison must be made to check if this summed-upvalue has reached the time stamp time designated by STB unit 416. Basedon the comparison result, the position of a stream block (SOBU) in astream object (SOB), which block includes the time stamp value thatmatches the time designated by STB unit 416, is detected.

[0488] AS shown in FIG. 21(c), the boundary position of each of pictureinformation 6010 to 6030 does not always match that of a stream block(SOBU).

[0489] In this case, as shown in, e.g., FIG. 21(a), if playback is to bestarted from the position of P-picture o with the PTS value= PTS No. 6,the following process is required.

[0490] More specifically, the value of PTS No. 2 of I-picture iimmediately before that picture is detected from time relationship table2 (the internal structure is the same as that shown in FIG. 20(b)) inFIG. 21(b), and playback must be started from the head position ofstream block (SOBU) #A that includes first transport packet #2 in whichI-picture information 6010 is recorded.

[0491] In this case, before playback progresses from the head positionof stream block (SOBU) #A to the position of desired P-picture o,picture information during that period (pictures i to n in FIG. 21(a))is not output to the external monitor (TV).

[0492]FIG. 22 is a view for explaining the relationship between thevideo information compression method in MPEG and transport packets, andthe relationship between transport packets in MPEG and applicationpackets in the streamer.

[0493] As shown in FIG. 22, broadcast signal information in digital TVadopts a signal compression method called MPEG2. In the signalcompression method based on MPEG, images (pictures) for TV display arecategorized into I-picture 551 that does not contain any timedifferential information, and B-pictures 553 and 554 and P-picture 552which contain time differential information.

[0494] I-picture independently exists without being influenced by theprevious or next image (picture) information, and after DCTtransformation for a single image (picture), quantized informationbecomes I-picture compressed information 561 and is recorded asI-picture information 31. As for P-picture 552, only differentialinformation 562 from I-picture 551 is recorded as P-picture information32. As for B-pictures 553 and 554, two pieces of differentialinformation from I-picture 551 and P-picture 552 are recorded as piecesof B-picture information 33 and 34.

[0495] Hence, upon video playback, P-picture 552 and B-pictures 553 and554 cannot solely generate images, but can generate picture images onlyafter the image of I-picture 551 is generated. Pieces of pictureinformation 31 to 34 are divisionally recorded in the payloads of one ora plurality of transport packets. At this time, the information isrecorded so that the boundary position of each of picture information 31to 34 always matches that between neighboring transport packets.

[0496] When transport packets in FIG. 22 are recorded by the streamer(optical disc device 415 in FIG. 19), the contents of transport packetsare transplanted to packets (application packets) with time stampscalled application time stamps (ATS).

[0497] A group of application packets with ATS (normally, around 10packets) are stored in an application packet area in a stream PESpacket.

[0498] One stream pack is formed by appending a pack header to thisstream PES packet.

[0499] The stream PES packet is made up of a PES header, substream ID,application header, application header extension (option), stuffingbytes (option), and application packet area for storing the group ofapplication packets with ATS.

[0500]FIG. 23 is a view for explaining the correspondence among thedigital broadcast contents, the video data transfer format in IEEE1394,and stream packs in the streamer.

[0501] In digital broadcast, video information compressed according toMPEG2 is transferred in transport packets. Each transport packet is madeup of transport packet header 511, and payload 512 that records a datamain body of recording information, as shown in FIG. 23(b).

[0502] Transport packet header 511 is comprised of payload unit startindicator 501, packet ID (PID) 502, random access indicator 503, programclock reference 504, and the like, as shown in FIG. 23(a).

[0503] The MPEG-compressed video information contains I-, B-, andP-picture information. In the first transport packet that recordsI-picture information, random access indicator 503 in FIG. 23(a) is setwith flag=“1”. On the other hand, in the first transport packets ofB-picture information and P-picture information, payload unit startindicator 501 in FIG. 23(a) is set with flag=“1”.

[0504] Using information of these random access indicator 503 andpayload unit start indicator 501, information of an I-picture mappingtable (641 in FIG. 9(e)) and information of a B/P-picture start positionmapping table (642 in FIG. 9(e)) are generated.

[0505] For example, a bit at the corresponding position in theB/P-picture start position mapping table (642 in FIG. 9(e)) is set at“1” for a transport packet having payload unit start indicator 501 shownin FIG. 23(a) set with flag=“1”.

[0506] In digital broadcast, video information and audio information aretransferred in different transport packets. The video information andaudio information are distinguished by packet ID (PID) 502 in FIG.23(a). Using information of this PID 502, a video packet mapping table(643 in FIG. 9(e)) and an audio packet mapping table (644 in FIG. 9(e))are generated.

[0507] As shown in FIG. 23(c), a plurality of programs (programs 1 to 3in this example) are time-divisionally transferred while beingpacketized in a single transponder.

[0508] For example, information of transport packet header 511 and thatof payload (recording information) 512 in FIG. 23(b) are transferred bytransport packets b·522 and e·525 of program 2 shown in FIG. 23(c).

[0509] When the user instructs to record, for example, the secondprogram in FIG. 23(c) on information storage medium 201, receptioninformation selector 423 in STB unit 416 shown in FIG. 19 extracts onlytransport packets b and e of program 2.

[0510] At that time, STB unit 416 appends reception time information oftransport packets b 522 and e 525 in the form of time stamps 531 and532, as shown in FIG. 23(d).

[0511] After that, when data is transferred to formatter/deformatter 413in FIG. 19 according to the IEEE1394 transfer scheme, the pairs of timestamps and transport packets are transferred while being segmented intosmall units, as shown in FIG. 23(e).

[0512] Formatter/deformatter 413 in FIG. 19 temporarily converts streamdata transferred by IEEE1394 from STB unit 416 into the format shown inFIG. 23(d) (corresponding to the format shown in FIG. 1(g)). A bitstreamin the format shown in FIG. 23(d) (a stream pack sequence in FIG. 23(h))is recorded on information storage medium 201.

[0513] More specifically, in an embodiment of the present invention,pack headers and PES headers which record system clock information andthe like are inserted at the head positions of respective sectors (seeFIG. 23(h), etc.).

[0514] A plurality of time stamps and transport packets (FIG. 1(g)) arepacked in data areas 21, 22, and 23 (FIG. 1(f)), and one transportpacket (packet d in FIG. 1(g); packet b of program 2 in FIG. 23(d)) isrecorded across a plurality of sectors (Nos. 0 and 1 in FIG. 1(e);partial packets in FIG. 23(f) and (g)). This is one feature of thepresent invention.

[0515] Using the data structure that utilizes this feature, a packethaving a size larger than the sector size (e.g., 2,048 bytes) can berecorded. This point will be described in more detail below.

[0516] Digital broadcast adopts a multi-program compatiblemultiplexing/demultiplexing scheme called a transport stream, as shownin FIG. 23(c), and one transport packet b·522 often has a size of 188bytes (or 183 bytes).

[0517] As described above, one sector size is 2,048 bytes, and each ofdata areas 21, 22, and 23 (FIG. 1(f)) can record approximately 10transport packets for digital broadcast even after various header sizesare subtracted.

[0518] By contrast, in a digital communication network such as ISDN orthe like, a long packet having a packet size as large as 4,096 bytes isoften transferred.

[0519] Using the data structure that utilizes the feature (capable ofrecording one packet data across a plurality of packets) so that each ofdata areas 21, 22, and 23 (FIG. 1(f)) can record not only a plurality oftransport packets, but also a packet with a large packet size such as along packet, one packet is recorded to extend across a plurality of dataareas 21, 22, and 23.

[0520] As a result, all packets, i.e., transport packets for digitalbroadcast, a long packet for digital communications, and the like can berecorded in a stream block without any fractions independently of theirpacket sizes.

[0521] A normal packet is appended with a time stamp. However, as shownin FIG. 23(g), a time stamp can be omitted in a partial packet.

[0522] In this manner, partial packets (the partial packet size fallswithin the range from 1 to 187 bytes if the packet size is 188 bytes; anaverage of less than 100 bytes) divided at the boundary of twoneighboring stream packs (FIG. 23(h)) can be effectively used ininformation recording. In addition, the storage capacity of medium 201can be increased by an amount of each time stamp (e.g., 4 bytes per timestamp) omitted from a partial packet.

[0523] Note that the position of a time stamp located immediately afterthe first packet in FIG. 23(g) can be specified by first access point625 in FIG. 10(b), or FIRST_AP_OFFSET shown in FIG. 10(c).

[0524] Optical disc device 415 (streamer) in FIG. 19 records pairs oftime stamps and transport packets (FIG. 23(f) and (g)) on informationstorage medium 201 without any conversion.

[0525]FIG. 24 is a flow chart for explaining the recording sequence ofstream data according to an embodiment of the present invention. Theprocess upon recording stream data will be explained using FIG. 24. Thisprocess can be implemented by a processing program stored in programmemory 404 a of STB controller 404 shown in FIG. 19.

[0526] As shown in FIG. 23(c), a plurality of pieces of programinformation are time-divisionally multiplexed in a single transponder.

[0527] Reception information selector 423 in FIG. 19 extracts atransport packet of only a specific program from a packet sequence ofthe plurality of time-divisionally multiplexed program information (stepS01).

[0528] The “reception time management unit (demodulator 422, receptioninformation selector 423, multiplexed information demultiplexer 425, STBcontroller 404 and the like in FIG. 19)” temporarily saves the requiredprogram information in memory 426 of multiplexed informationdemultiplexer 425 (step S02).

[0529] At the same time, reception times in units of transport packetsare measured, and the measurement values are appended to the respectivetransport packets (or application packets) as time stamps (ATS), asshown in FIG. 23(d). Each time stamp information appended in this way isrecorded in memory 426 (step S03).

[0530] The “stream data content analysis unit (multiplexed informationdemultiplexer 425, STB controller 404, and the like in FIG. 19)”analyzes information in the transport packets (application packets)recorded in memory 426.

[0531] More specifically, each picture boundary position is extractedfrom the transport packet (application packet) sequence, and PTSinformation (or information of the number of corresponding fields) isextracted from picture header information 41 of each packet (step S04).

[0532] There are two different picture boundary position extractionmethods, and one of these methods is selected depending on the contentsof stream data.

[0533] In the first picture boundary position extraction method, anI-picture position is detected by detecting the flag of random accessindicator 503 (FIG. 23(a)) in transport packet header 511 (FIG. 23(b)),a B- or P-picture position is detected by detecting the flag of payloadunit start indicator 501 (FIG. 23(a)).

[0534] In the second picture boundary position extraction method,picture identification information 52 (FIG. 1(k)) and PTS information 53(FIG. 1(k)) in picture header information 41 (FIG. 1(j) are extracted.

[0535] After the aforementioned processes (steps S01 to S04), the “timerelated information generation unit (multiplexed informationdemultiplexer 425, STB controller 404, data transfer interface 420, andthe like in FIG. 19)” generates time relationship table 2 (or playbacktime stamp list PTSL in FIG. 15) as a list which indicates therelationship between the time stamps (ATS) and PTS values, and recordsit in work memory 407 in STB controller 404 (step S05).

[0536] Then, packet data (stream data) temporarily saved in memory 426of multiplexed information demultiplexer 425 are transferred to opticaldisc device 415 while maintaining the reception time interval betweenSTB unit 416 and optical disc device 415 (i.e., while maintainingconstant the relationship between a change in count value of STC 440 anda change in count value of STC 424 in FIG. 19) (step S06).

[0537] In this way, optical disc device 415 records the stream datatemporarily saved in memory 426 on information storage medium 201 (stepS07).

[0538] The processes in steps S06 and S07 repeat themselves until streamdata transfer to optical disc device 415 is completed (NO in step S08).

[0539] Upon completion of stream data transfer to optical disc device415 and completion of its video recording process (YES in step S08),information of time relationship table 2 (or playback time stamp listPTSL) temporarily recorded in work memory 407 of STB controller 404 istransferred to optical disc device 415 (step S10).

[0540] Information of time relationship table 2 (or playback time stamplist PTSL) is recorded in management information recording area(STREAM.IFO) 105 of information storage medium 201 (step S11).

[0541] Upon processing step S11, the recording time (SOB_REC_TM in FIG.7(i)) of a stream object as the content of the recorded stream data canbe recorded in time zone (TM_ZONE) 6240 (FIG. 7(h)).

[0542] Encrypted stream data is often recorded for the purpose ofcopyright protection of the contents provider upon recording streamdata. When encryption is made in this way, all transport packets areencrypted, and a time stamp transfer process between STB unit 416 andoptical disc device 415 is inhibited. In such case, optical disc device415 must individually append time stamps upon recording (encrypted)stream data on information storage medium 201.

[0543] STB unit 416 in FIG. 19 makes reception time management in unitsof transport packets (application packets). In this case, a measureagainst reference clock frequency errors (more specifically,synchronization of reference clocks) between STB unit 416 and opticaldisc device 415 is an important subject. Hence, a video recordingprocess of encrypted stream data will be explained below.

[0544]FIG. 25 is a flow chart for explaining the recording sequence ofencrypted stream data according to an embodiment of the presentinvention. This processing sequence can be implemented by a processingprogram stored in program memory 404 a of STB controller 404 shown inFIG. 19.

[0545] It is checked if time relationship table 2 (FIG. 20(b)) orplayback time stamp list PTSL (FIG. 15) is present in work memory 407 ofSTB controller 404 in FIG. 19 (step S50).

[0546] If no time relationship table (or PTSL) is present (NO in stepS50), the time relationship table (or PTSL) is generated by the sameprocesses as in steps S04 and S05 in FIG. 24 (step S52).

[0547] After the time relationship table (or PTSL) is generated or ifthe time relationship table (or PTSL) is already present in work memory407 of STB controller 404 (YES in step S50), (encrypted) stream data istransferred from STB unit 416 to optical disc device 415 and is recordedon information storage medium 201 (step S51).

[0548] The process in step S51 continues until recording of the(encrypted) stream data is completed (NO in step S53). This stream datarecording step S51 has the same processing contents as those in stepsS01 to S03 and S06 in FIG. 24.

[0549] Note that the process in step S52 may be executed parallel tostep S51 during processing of step S51.

[0550] Upon completion of recording of the (encrypted) stream data (YESin step S53), a reference clock synchronization process is executedbetween STB unit (or STB device) 416 and optical disc device (or opticaldisc drive) 415 (step S54).

[0551] This reference clock synchronization process can be executed,e.g., as follows.

[0552] That is, upon transfer of stream data, every time a specificnumber of transport packets (application packets) (e.g., 10,000 or100,000 packets) are sent/received, STB unit 416 and optical disc device415 respectively record the send/reception time in their work memory 407and temporary storage 411.

[0553] After that, every time STB unit 416 sends a specific number oftransport packets (application packets) to optical disc device 415, itappends a send time list. Optical disc device 415 compares the receivedlist and a list created by itself in advance, thus computing anyreference clock synchronization error therebetween.

[0554] After that, STB unit 416 transfers time relationship table 2 (orPTSL) to optical disc device 415 (step S55).

[0555] Time relationship table 2 (or PTSL) transferred from STB unit 416to optical disc device 415 in this way is corrected on the basis of thereference clock synchronization error computed in the reference clocksynchronization process in step S54 (step S56).

[0556] Time relationship table 2 (or PTSL) which has been correctedbased on the reference clock synchronization error is recorded in themanagement information area (STREAM.IFO 105 in FIG. 3(e); or SFIT inFIG. 15) of information storage medium 201 (step S57).

[0557] In this fashion, (encrypted) stream data can be recorded/playedback.

[0558] In place of the aforementioned method of “correcting thereference clock synchronization error for encrypted stream data”,another method may be used as follows.

[0559] That is, as shown in FIG. 20(b), the number of transport packetstransferred between neighboring I-pictures is recorded in timerelationship table 2. Then, the total number of transport packets (orapplication packets) from the head of a cell is designated in place ofthe time stamp value of a playback start image (as the picturedesignation method).

[0560] In this case, the number of transport packets (or the numberAP_Ns of application packets) included in each stream block is providedas information in time map information 252 in place of the datastructure shown in FIG. 3(i), as shown in FIG. 11.

[0561] When STB unit 416 designates the total number of transportpackets (the total number of application packets) to access apredetermined image (picture), optical disc device 415 sums up thenumbers 633 of transport packets (application packets) in turn from thefirst stream block shown in FIG. 11, and accesses a stream block (orSOBU) when the summed-up result has reached the designated value.

[0562]FIG. 26 is a flow chart for explaining the playback sequence ofstream data according to an embodiment of the present invention. Thisprocessing sequence can be implemented by a processing program stored inprogram memory 404 a of STB controller 404 shown in FIG. 19. Theplayback steps of stream data will be explained below using FIG. 26.

[0563] The user can designate a desired playback start time and/orplayback end time in the form of a “differential time (xx hours yyminutes zz seconds) with reference to the display start time of thedesignated original cell”. STB controller 404 in STB unit 416 receives,e.g., a specific playback start time and playback end time designated inthis way (step S21).

[0564] STB controller 404 converts the time information of the receivedplayback start time and playback end time into clock count values of 27MHz and/or 90 kHz, and computes differential PTS values from the displaystart time of the original cell.

[0565] STB controller 404 controls optical disc device 415 to read timerelationship table 2 (or PTSL) recorded in the stream data managementinformation recording area (STREAM.IFO 105), and temporarily records itin work memory 407 (step S22).

[0566] Also, STB controller 404 controls optical disc device 415 to readtime map information 252 (or MAPL) recorded in the stream datamanagement information recording area (STREAM.IFO 105), and temporarilyrecords it in work memory 407 (step S23).

[0567] Then, STB controller 404 reads the value of PTS offset 9 shown inFIG. 3(h) and FIG. 20(a), and checks the difference (PTS No. 5−PTS No. 1in FIG. 20(a)) between the display start time of the correspondingoriginal cell (corresponding to B-picture f in FIG. 20(a)) and thedisplay time of I-picture a immediately before that picture (step S24).

[0568] Furthermore, STB controller 404 reads the value of PTS offset 9shown in FIG. 3(h) and FIG. 20(a), and computes the PTS values of theplayback start time and playback end time designated by the user bysumming up:

[0569] (A) the read value (PTS offset 9),

[0570] (B) the PTS value at the I-picture a position immediately beforethe display start time of the original cell (when display start picturef of the original cell is located immediately after I-picture a as inFIG. 20(a)), and

[0571] (C) the differential PTS value (PTS No. 5−PTS No. 1) checked instep S24 (step S25).

[0572] STB controller 404 then checks the value of the PTS value ofI-picture i immediately before the playback start position designated bythe user, and the value of time stamp #2 using time relationship table 2(step S26), and informs optical disc device 415 of them.

[0573] The optical disc device checks the value of first time stamp(ATS) #1 of stream block (SOBU) #A that includes the head position ofthat I-picture i information (FIG. 21(c)) from data (FIG. 3(i)) of timemap information 252 shown in FIG. 3(h), and detects the location(address) of first sector #α to be accessed (step S27).

[0574] Based on the detected address, optical disc device 415 plays backinformation from transport packet (AP) #1 in FIG. 21(c) from informationstorage medium 201 (step S28).

[0575] STB controller 404 in FIG. 19 then informs decoder unit 402 ofthe PTS value (PTS No. 6 in FIG. 21(a)) indicating the display starttime of information which has begun to be played back in step S28 (stepS29).

[0576] Together with this information, optical disc device 415 transfersthe information which has begun to be played back in step S28 (stepS30).

[0577] Subsequently, STB controller 404 reads picture identificationinformation 52 (FIG. 1(k)) from memory 426 in decoder unit 402, anddiscards (or ignores) data before the input I-picture (a portion of theinformation transferred from optical disc device 415) (step S31).

[0578] Video decoder 428 in FIG. 19 then starts decoding from the headposition of the I-picture (I-picture i in FIG. 21(a)) input in step S31,and starts display (video output) from the position of the PTS value(PTS No. 6 in FIG. 21(a)) designated by the information in step S29(step S32).

[0579] The same processes as in steps S24 to S28 are repeated, and theaddress on the information storage medium 201, which corresponds to theplayback end time is checked to proceed with playback until the endaddress corresponding to the playback end time (step S33).

[0580] Upon completion of a series of playback processes, playback endposition information 6110 shown in FIG. 7(g) can be recorded as resumeinformation in video manager information (FIG. 7(f)) in the managementinformation recording area (STREAM.IFO 105 shown in FIG. 7(e)).

[0581] As the data contents of this playback end position information6110, corresponding PGC number 6210, cell number 6220 therein, andplayback end position time information 6230 are recorded, as shown inFIG. 7(h).

[0582] This time information 6230 is recorded as the time stamp value,but the PTS value (or the total number of fields from the cell playbackstart position) can be recorded as time information 6230.

[0583] When playback of this playback end position information isrestarted from the position of (resume) information 6110 based on thisplayback end position information, the playback start position can beobtained by the process shown in FIG. 27 (to be described later).

[0584] In standard playback mentioned above with reference to FIG. 26,decoding in decoder unit 402 starts from the time when the count valueof STC unit 424 as the reference clock generator in STB unit 416 hasmatched the value of DTS (decode time stamp) information 54 shown inFIG. 1(k).

[0585]FIG. 27 is a flow chart for explaining the special playbacksequence of stream data according to an embodiment of the presentinvention. This processing sequence can be implemented by a processingprogram stored in program memory 404 a of STB controller 404 shown inFIG. 19.

[0586] Upon executing special playback such as fastforward (FF) playbackor fast reverse (FR) playback, only I-picture information recorded oninformation storage medium 201 is extracted and played back, and isdecoded and displayed.

[0587] In this case, a “special playback mode setup” is made in decoderunit 402 to decode in a free mode by canceling synchronization betweenSTC unit 424 (FIG. 19) and DTS information 54 (FIG. 1(k)) (step S41).

[0588] In special playback as well, time relationship table 2 and timemap information 252 are read from management information recording area(STREAM.IFO) 105 of information storage medium 201, and are recorded inwork memory 407 of STB controller 404 (step S42).

[0589] Then, time map information 252 of stream object information(SOBI) 242 corresponding to the playback start position of interest isread, and is temporarily stored in work memory 407 in STB controller 404(step S43).

[0590] The time stamp values of the start time/end time at eachI-picture position (the position of each AU# in the example shown inFIG. 16) are then extracted from time relationship table 2 (step S44).

[0591] A stream block (SOBU) that includes the time stamp value of theI-picture of interest is checked from time map information 252, and theaddress of its first sector is checked (step S45).

[0592] Upon special playback, only I-picture information 6010 to 6050 inFIG. 28(b) to be described later are decoded and displayed. Thepositions of I-picture information 6010 to 6050 can be obtained usingthe information of time relationship table 2 and time map information252.

[0593] Optical disc device 415 then plays back information in all streamblocks (SOBUS) that contain I-pictures on information storage medium201, and transfers played-back information to memory 426 in multiplexedinformation demultiplexer 425 (step S46).

[0594] Decoder 402 in FIG. 19 reads picture identification information52 (FIG. 1(k)) in the data transferred to memory 426 in multiplexedinformation demultiplexer 425, and discards data other than I-pictureson the basis of this information 52 (step S47).

[0595] That is, in step S47 only I-picture information is extracted fromthe played back and transferred stream data using picture identificationinformation 52, and video decoder 428 decodes only the extractedI-picture information.

[0596] The I-picture data sorted (i.e., not discarded) in memory 426 ofmultiplexed information demultiplexer 425 in decoder unit 402 aretransferred to frame memory 406 (step S48).

[0597] The I-picture data transferred to frame memory 406 in this wayare sequentially displayed on the display screen of TV (or videomonitor) 437 (step S49).

[0598]FIG. 28 is a view for explaining a time relationship tableindicating the relationship between the display time and data transfertime in another embodiment of the present invention.

[0599] In the embodiment shown in FIG. 20, absolute value display ismade as display time information, as shown in FIG. 20(b). Instead,differential information between neighboring I-pictures (e.g.,information indicating the number of fields inserted between neighboringI-pictures) may be used.

[0600] In FIG. 20(b), “PTS” information is used as the time displayinformation. However, an embodiment of the present invention that allowsvarious modifications is not limited to such specific method. Instead,“the number of differential fields from a specific reference image(picture)”, “date & time information”, or the like can be used. Anexample in this case is time relationship table 6 shown in FIG. 28.

[0601] As shown in FIG. 28(b), each group of pictures (GOP) is a picturegroup which has a given I-picture position as the head position andincludes pictures from that I-picture to a picture immediately beforethe next I-picture. In the data structure of time relationship table 6shown in FIG. 28(c), the number of display fields in units of GOPS isrecorded as display time information.

[0602] Also, time relationship table 6 describes the number of streamblocks (SOBUs) occupied in units of GOPS. In this way, a stream block(SOBU) which records the head position of I-picture information can bedirectly accessed from the input display time information without usingtime map information 252 shown in FIG. 3(h).

[0603] At the boundary position between GOP#2 and GOP#3 in the exampleshown in FIG. 28(b), the switching position of GOPs matches that ofstream blocks (SOBUs). When the boundary of neighboring GOPs matchesthat of neighboring SOBUs in this manner, a GOP end matching flag intime relationship table 6 shown in FIG. 28(c) is set at “1”. In thisway, identification precision of the stream block position (SOBUposition) that includes the I-picture information head position isimproved.

[0604] Since special playback such as FF, FR, or the like uses thetrailing end position of I-picture information, time relationship table6 in FIG. 28(c) also has I-picture size information in each GOP.

[0605]FIG. 29 is a view for explaining the way packets (AP) in streamdata (SOBU) are played back in an embodiment of the present invention.

[0606]FIG. 29 exemplifies a case wherein all stream blocks #1, #2, . . .in FIG. 1(c) are made up of SOBU#1, SOBU#2, . . . each having a fixedsize (2-ECC block size).

[0607]FIG. 29(f) shows the data structure of first sector No. 0 (FIG.29(e)) of SOBU#1, and that of end sector No. 63 (FIG. 29(e)) of SOBU#2that neighbors SOBU#1. Although not shown, sectors No. 0 to No. 62 havethe same structure.

[0608] As shown in FIG. 29(f), the pack header of a stream packcorresponding to sector No. 0 records system clock reference SCR, andthat of a stream pack corresponding to sector No. 63 also records systemclock reference SCR.

[0609] Assume that a picture to be played back (a picture that the userdesignates using the playback time) is located at the middle of SOBU#2(e.g., the position indicated by AU#1 in FIG. 16). The picture that theuser designates using the playback time corresponds to cell startapplication packet arrival time SC_S_APAT.

[0610] In this case, the disc drive (not shown) included inrecording/playback unit 409 in FIG. 19 cannot directly access the middleposition of SOBU#2, and accesses the boundary position between SOBU#1and SOBU#2. Playback of stream data (STREAM.IFO) 106 in FIG. 29(a)starts from the boundary position between SOBU#1 and SOBU#2.

[0611] The interval from the boundary position between SOBU#1 and SOBU#2to the playback start position (the position corresponding to SC_S_APAT)corresponds to PTS offset 9 described in FIG. 20(a).

[0612] Application packets present between the boundary position betweenSOBU#1 and SOBU#2 and the playback start position (the positioncorresponding to SC_S_APAT) are decoded but are not played back andoutput (not displayed on the screen). This corresponds to the process instep S31 in FIG. 26.

[0613]FIG. 29(g) illustrates that PTS information (PTS value or PTSoffset) and application packet AP to be played back are related via timerelationship table 2 in FIG. 20(a).

[0614] The relationship between the time relationship table and playbacktime stamp PTSL shown in FIG. 15 are summarized below.

[0615] If ATS represents the time stamp shown in FIG. 1(g), etc., thePTS value included in playback time stamp list PTSL shown in FIG. 15 andATS have the following relationship:

[0616] (1) a stream cell looks up a portion of the recorded bitstream;

[0617] (2) AU (normally, I-picture) is a continuous portion of therecorded bitstream (or, AU corresponds to a portion of a cell);

[0618] (3) which SOBU includes the AU (I-picture corresponding to aportion of a cell) is indicated by AUSM (see FIG. 16);

[0619] (4) the PTS value is the playback time (display time; orpresentation time PTM) of the corresponding AU (i.e., the PTS valuecorresponding to AU represents, with respect to playback time, a portionof a cell);

[0620] (5) cell start APAT (SC_S_APAT) is the arrival time ofapplication packet AP of the cell of interest (SC_S_APAT corresponds tothe PTS value with respect to or in association with the playback time);

[0621] (6) application packet AP includes time stamp ATS at its headposition (see FIG. 29(g),etc.);

[0622] (7) the PTS value is included in PTSL (see FIG. 15); and

[0623] (8) from the above facts, the PTS value included in PTSLcorresponds to ATS through the mediation of AUSM, SC_S_APAT, and thelike.

[0624] Therefore, playback time stamp list PTSL can be regarded as “timerelationship table (FIG. 20(b))” including information (PTS value)indicating the relationship (relationship pertaining to the playbacktime) between the start time (SC_S_APAT) of AU (I-picture) and timestamp ATS of a packet included in the bitstream.

[0625] Or, PTSL (time relationship table) can be regarded as informationindicating the correspondence between the PTS value and ATS.

[0626] Finally, meanings of some terms used in the description of theembodiments will be summarized below.

[0627] A stream object (SOB) indicates data of the recorded bitstream.The SR_TRANS.SRO file can record a maximum of 999 SOBs.

[0628] A stream object unit (SOBU) is a basic unit organized in an SOB.That is, each SOB is made up of a chain of SOBUs. Especially afterediting, the head SOBU and/or end SOBU of SOB often contain or containsdata which does not belong to an effective portion of that SOB.

[0629] The SOBU is characterized not by the playback time or playbackorder but by a fixed size (size for 32 sectors or for two ECC blocks).

[0630] An access unit (AU) indicates an arbitrary, single, continuousportion in the recorded bitstream suitable for individual playback. ThisAU normally corresponds to I-picture in the MPEG-encoded bitstream.

[0631] An access unit start map (AUSM) indicates an SOBU in the SOB ofinterest, which includes the AU.

[0632] An application packet (AP) is a portion of a bitstream comingfrom an application device during recording. Or, the AP is a portion ofa bitstream that goes to an application device during playback. Such APis included in a multiplexed transport and has a fixed size (a maximumof 64,574 bytes) during recording.

[0633] An application time stamp (ATS) is inserted before each AP, andconsists of 32 bits (4 bytes). The ATS is made up of a basic field of 90kHz and an extended field of 27 MHz.

[0634] A cell (or stream cell SC) is the data structure indicating aportion of a program. A cell in an original PGC is called an originalcell, and a cell in a user-defined PGC is called a user-defined cell.Each program in a program set is formed of at least one original cell.Each portion of a program in each play list is made up of at least oneuser-defined cell. In the streamer, a “cell” indicates a stream cell(SC). Each SC looks up a portion of the recorded bitstream.

[0635] The cell number (CN) is a number (1 to 999) assigned to each cellin a PGC.

[0636] Stream cell entry point information (SC_EPI) can be used as atool for partially skipping recorded contents, and can be present in anarbitrary stream cell (SC).

[0637] A start application packet arrival time (SOB_S_APAT) of a streamobject indicates the arrival time of the first AP that belongs to theSOB of interest. This arrival time is made up of a basic field of 90 kHzand an extended field of 27 MHz.

[0638] An end application packet arrival time (SOB_E_APAT) of a streamobject indicates the arrival time of the last AP that belongs to the SOBof interest.

[0639] A start application packet arrival time (SC_S_APAT) of a streamcell indicates the arrival time of the first AP that belongs to the SCof interest.

[0640] An end application packet arrival time (SC_E_APAT) of a streamcell indicates the arrival time of the last AP that belongs to the SC ofinterest.

[0641] Navigation data can be used to control recording, playback,editing of the bitstream (SOB).

[0642] A play list (PL) is a list of program portions, the sequence ofwhich can be arbitrarily defined by the user. PL is described as auser-defined PGC. +p1 A program (PG) is a logical unit of the recordedcontents, which is recognized or defined by the user. A program in aprogram set is formed of one or more original cells. A program isdefined in only an original PGC.

[0643] A program chain (PGC) is a generic unit. In an original PGC, thePGC indicates a chain of programs corresponding to a program set. On theother hand, in a user-defined PGC, the PGC corresponds to a play listand indicates a chain of portions of programs.

[0644] Program chain information (PGCI) is the data structure indicatingplayback of an overall PGC. The PGCI is used in either an original PGCor user-defined PGC. The user-defined PGC is formed of only PGCI, andits cell looks up an SOB in the original PGC.

[0645] The program chain number (PGCN) is a serial number (1 to 99)assigned to each user-defined PGC.

[0646] The program number (PGN) is a serial number (1 to 99) assigned toeach program in the original PGC.

[0647] A program set indicates the entire recorded contents of a disc(recording medium), which consist of all programs. If any program doesnot undergo edit that changes the playback order from originalrecording, the same playback order as the recording order of programs isused upon playing back the program set.

[0648] “Real-time recording” is a recording performance that can record,even when a buffer memory size is limited, stream data on a disc(recording medium) without overflowing the buffer memory, provided thatany stream data encoded at a limited transfer rate is transferred at thelimited transfer rate.

[0649] The advantageous effects of the embodiments according to thepresent invention are summarized as follows:

[0650] 1. By providing information (time relationship table or PTSL)that indicates the relationship between time stamp data (ATS) recordedin stream data and display time information (PTS or field information)to a portion of management information (SFIT), playback/screen displaycan be started with high precision from the display time designated bythe user.

[0651] 2. The user can designate a partial erase range or re-arrangementdesignation range of the recorded stream data using the display time onthe monitor TV.

[0652] As in item “1.” above, the time relationship table (or PTSL)indicating the relationship between time stamp data and display timeinformation is provided as a portion of management information (SFIT).In this manner, the position of edit point (for partial erase range,re-arrangement designation range, or the like) can be accurately setusing this time relationship table (or PTSL). As a result, timemanagement for stream data can be made using time stamp data (ATS), andan accurate edit process according to a user's request can beguaranteed.

[0653]3. As in item “1.” above, since the time relationship table (orPTSL) is included in stream data, the playback start position uponrestarting the streamer (resume playback start position) can beaccurately set by only describing either time stamp data (ATS) ordisplay time information (PTS) as the playback end position information(resume position).

[0654] 4. If the playback end position information (resume information)is recorded using time stamp data (ATS), when a specific position on theinformation storage medium is accessed, the address to be accessed canbe quickly detected using time map information 252.

[0655] 5. MPEG-compressed data requires playback to start fromI-picture. By recording information (time relationship table) indicatingthe relationship between the time stamp data (ATS) and display timeinformation (PTS or field information) at each I-picture start position(or start position of access unit AU), access control to desiredI-picture (desired AU) can be made at high speed using time mapinformation 252.

[0656] 6. By recording information (time relationship table) indicatingthe relationship between the time stamp data (ATS) and display timeinformation (PTS or field information) at each I-picture start position(or start position of each AU), the address of the stream block (orSOBU) position including I-picture (AU) can be detected in combinationwith time map information 252. For this reason, a special playbackprocess such as fastforward FF, fast reverse FR, or the like that playsback and displays only I-pictures can be done.

[0657] Additional advantages and modifications will readily occur tothose skilled in the art. Therefore, the invention in its broaderaspects is not limited to the specific details and representativeembodiments shown and described herein. Accordingly, variousmodifications may be made without departing from the spirit or scope ofthe general inventive concept as defined by the appended claims andtheir equivalents.

What is claimed is:
 1. An information medium which has a data area inwhich stream data can be recorded in a predetermined data recordingunit, and a management area in which management information thatpertains to the stream data can be recorded, wherein the managementinformation can record: first management information used to access thestream data; second management information, being different from thefirst management information, used to access the stream data; and thirdmanagement information indicating a relationship between the firstmanagement information and second management information.
 2. Aninformation medium according to claim 1 , wherein the stream dataincludes a bitstream compressed based on MPEG, and the second managementinformation corresponds to a playback time of the stream data.
 3. Aninformation medium according to claim 1 , wherein the managementinformation includes a stream file information table which manages astream object that forms a portion of contents of the stream data, thestream file information table includes stream object information thatmanages the stream object, and the stream object information includesaccess unit general information including the first managementinformation, and the third management information.
 4. An informationmedium according to claim 1 , wherein the first management informationincludes information used upon transferring the stream data, and thesecond management information includes information used upon displayingthe stream data.
 5. An information medium according to claim 2 , whereinthe first management information includes information used upontransferring the stream data, and the second management informationincludes information used upon displaying the stream data.
 6. Aninformation medium according to claim 3 , wherein the first managementinformation includes information used upon transferring the stream data,and the second management information includes information used upondisplaying the stream data.
 7. An information medium according to claim1 , which has a data area in which stream data can be recorded in apredetermined data recording unit, a management area in which managementinformation that pertains to the stream data can be recorded, and firsttime management information that pertains to the stream data, whereinthe management information includes recording information of the streamdata.
 8. An information medium according to claim 2 , which has a dataarea in which stream data can be recorded in a predetermined datarecording unit, a management area in which management information thatpertains to the stream data can be recorded, and first time managementinformation that pertains to the stream data, wherein the managementinformation includes recording information of the stream data.
 9. Aninformation medium according to claim 3 , which has a data area in whichstream data can be recorded in a predetermined data recording unit, amanagement area in which management information that pertains to thestream data can be recorded, and first time management information thatpertains to the stream data, wherein the management information includesrecording information of the stream data.
 10. An information mediumaccording to claim 4 , which has a data area in which stream data can berecorded in a predetermined data recording unit, a management area inwhich management information that pertains to the stream data can berecorded, and first time management information that pertains to thestream data, wherein the management information includes recordinginformation of the stream data.
 11. An information medium according toclaim 1 , which has a data area in which stream data can be recorded ina predetermined data recording unit, a management area in whichmanagement information that pertains to the stream data can be recorded,first time management information that pertains to the stream data, anda time management unit which is different from the first time managementinformation and pertains to a playback time of the stream data, whereinthe management information includes recording management informationthat pertains to recording of the stream data, and the time managementinformation that pertains to recording is described in a format of thefirst time management information or the time management unit thatpertains to the playback time.
 12. An information medium according toclaim 2 , which has a data area in which stream data can be recorded ina predetermined data recording unit, a management area in whichmanagement information that pertains to the stream data can be recorded,first time management information that pertains to the stream data, anda time management unit which is different from the first time managementinformation and pertains to a playback time of the stream data, whereinthe management information includes recording management informationthat pertains to recording of the stream data, and the time managementinformation that pertains to recording is described in a format of thefirst time management information or the time management unit thatpertains to the playback time.
 13. An information medium according toclaim 3 , which has a data area in which stream data can be recorded ina predetermined data recording unit, a management area in whichmanagement information that pertains to the stream data can be recorded,first time management information that pertains to the stream data, anda time management unit which is different from the first time managementinformation and pertains to a playback time of the stream data, whereinthe management information includes recording management informationthat pertains to recording of the stream data, and the time managementinformation that pertains to recording is described in a format of thefirst time management information or the time management unit thatpertains to the playback time.
 14. An information medium according toclaim 4 , which has a data area in which stream data can be recorded ina predetermined data recording unit, a management area in whichmanagement information that pertains to the stream data can be recorded,first time management information that pertains to the stream data, anda time management unit which is different from the first time managementinformation and pertains to a playback time of the stream data, whereinthe management information includes recording management informationthat pertains to recording of the stream data, and the time managementinformation that pertains to recording is described in a format of thefirst time management information or the time management unit thatpertains to the playback time.
 15. An information medium according toclaim 7 , which has a data area in which stream data can be recorded ina predetermined data recording unit, a management area in whichmanagement information that pertains to the stream data can be recorded,first time management information that pertains to the stream data, anda time management unit which is different from the first time managementinformation and pertains to a playback time of the stream data, whereinthe management information includes recording management informationthat pertains to recording of the stream data, and the time managementinformation that pertains to recording is described in a format of thefirst time management information or the time management unit thatpertains to the playback time.
 16. An information recording method thatuses an information medium which has a data area in which stream datacan be recorded in a predetermined data recording unit, and a managementarea in which management information that pertains to the stream datacan be recorded, wherein the management information can record firstmanagement information used to access the stream data; second managementinformation, being different from the first management information, usedto access the stream data; and third management information indicating arelationship between the first management information and secondmanagement information, said information recording method comprising:extracting the first management information from stream data to berecorded; extracting the second management information from the streamdata to be recorded; recording the stream data in the data area of saidinformation medium; and recording the third management information inthe management area of said information medium.
 17. An informationrecording method that employs a stream data recording device forrecording stream data, using a predetermined reference clock, obtainedfrom a stream data supply device, and that employs an information mediumwhich has a data area in which stream data can be recorded in apredetermined data recording unit, and a management area in whichmanagement information that pertains to the stream data can be recorded,wherein the management information can record first managementinformation used to access the stream data; second managementinformation, being different from the first management information, usedto access the stream data; and third management information indicating arelationship between the first management information and secondmanagement information, said information recording method comprising:executing a synchronization process of the predetermined reference clockbetween the stream data supply device and the stream data recordingdevice; correcting or modifying the third management information basedon a result of the synchronization process of the reference clock; andrecording the corrected or modified third management information in themanagement area of the information medium.
 18. An information recordingmethod according to claim 17 , wherein the third management informationis created before the synchronization process of the reference clock isexecuted.
 19. An information playback method that employs a stream dataplayback device having an internal clock, said information playbackmethod comprising: adjusting said internal clock to the predeterminedreference clock when said stream data playback device plays back thestream data from the information medium on which information is recordedaccording to the method of claim 17 .
 20. An information playback methodfor playing back stream data from an information medium which has a dataarea in which the stream data can be recorded in a second data unitincluding a first data recording unit, and a management area in whichmanagement information that pertains to the stream data can be recorded,wherein the management information can record first managementinformation used to access the stream data; second managementinformation, being different from the first management information, usedto access the stream data; and third management information indicating arelationship between the first management information and secondmanagement information, said information playback method comprising:when the stream data has a plurality of continuous second data units,checking a position difference from a neighboring boundary position ofthe plurality of continuous second data units to a position of the firstdata recording unit indicated by the second management information;starting read of the stream data recorded on the information medium fromthe neighboring boundary position but discarding or ignoring read datauntil the position of the first data recording unit indicated by saidposition difference; and starting playback of the stream data recordedon the information medium from the position of the first data recordingunit indicated by said position difference.
 21. An information playbackmethod for playing back stream data from an information medium which hasa data area in which the stream data can be recorded in a second dataunit including a first data recording unit, and a management area inwhich management information that pertains to the stream data can berecorded, wherein the management information can record first managementinformation used to access the stream data; second managementinformation, being different from the first management information, usedto access the stream data; and third management information indicating arelationship between the first management information and secondmanagement information, said information playback method comprising:checking a start address of the second data unit including the firstmanagement information; discarding or ignoring playback informationother than an access position of the stream data indicated as the firstmanagement information, using the checked start address of the seconddata unit; and sequentially playing back or sequentially displaying onlyplayback information at the access position of the stream data.
 22. Adata structure applicable to an information medium which has a data areain which stream data can be recorded in a predetermined data recordingunit, and a management area in which management information thatpertains to the stream data can be recorded, wherein the managementinformation is capable of recording first management information used toaccess the stream data; second management information, being differentfrom the first management information, used to access the stream data;and third management information indicating a relationship between thefirst management information and second management information.